There are no problems with spelling since /p/ is always <p> or <pp>, while /b/ is always <b> or <bb>.
There were a number of pairs where the contrast occurred twice, such as pop/bob. I have left in one or two of the more interesting ones, such as purple/burble, though I removed most such pairs, since they are not really minimal.
The difference between these sounds is small enough to be a problem for many learners, especially when the sound is final in a monosyllable. This is a recognised difficulty for German and Dutch speakers, but even native speakers of English can make mistakes in rapid speech. When the contrasts is initial, it is a known problem for Arabic speakers. (I once had an essay from an Arabic-speaking student who wrote about "the Pig Pen watch", meaning Big Ben). It may also be a problem to some extent for speakers of Indian languages which use unaspirated initial voiceless stops and Southeast Asian languages which make a phonemic contrast between aspirated and unaspirated voiceless stops.
As usual, I have included inflected forms such as ropes/robes and roped/robed even though they are not strictly minimal. See the main page for an explanation.
The contrast may be neutralised after /s/ or /z/. Thus there is hardly any difference between "the spread" and "this bread" or between "taste buds" and "taste spuds", as was cleverly exploited by the small local business selling baked potatoes in Shaftesbury.
Several taboo words occur in potentially embarrassing contrasts, such as crap/crab, peeing/being, and nipple/nibble.
Interesting pairs include:
ample ambleThe density value is 4.9%. The list makes 322 semantic contrasts, giving a semantic loading of 53%.
callipers calibres
oppressed abreast
pearly burly
plunder blunder
pullet bullet
pumpkin bumpkin
simple symbol
staple stable
alp alb ample amble apace abase ape Abe apportion abortion apportions abortions calipers calibres callipers calibres camper camber campers cambers cap cab caper caber capers cabers cop cob copper cobber coppers cobbers crap crab crapping crabbing craps crabs crumple crumble crumpled crumbled crumples crumbles crumpling crumbling cup cub cups cubs dapple dabble dappled dabbled dapples dabbles dappling dabbling dep deb dipper dibber dippers dibbers disperse disburse dispersed disbursed disperses disburses dispersing disbursing Epping ebbing fop fob gap gab GP GB grippe grebe gyp jib gypping jibbing harper harbour harpers harbours hop hob hops hobs knap nab knapping nabbing lap lab laps labs lip lib lips libs lop lob lopping lobbing lops lobs lope lobe lopes lobes maple Mabel Marple marble mop mob mopping mobbing MP MB nap nab napping nabbing nip nib nipple nibble nipples nibbles op ob open Oban oppressed abreast P B P's B's P be P bee P's bees pa baa pa bah pa bar PA BA pace base paced based pacing basing paces bases pace bass paces basses paced baste pack back packed backed packing backing packs backs packer backer packers backers pact backed pad bad pad bade pail bail pails bails pail bale pails bales pain bane pains banes painful baneful painfully banefully pair bare paired bared pairs bares pairing baring pale bail paled bailed paling bailing pales bails pale bale paled baled pales bales paling baling palate ballot palates ballots pall ball palled balled palling balling palls balls pall bawl palled bawled palling bawling palls bawls palled bald pally bally palm balm palmy balmy palmier balmier palmiest balmiest palm barm palmy barmy pan ban panned banned panning banning pans bans pang bang pangs bangs pang bhang pangs bhangs panga Bangor panned band pans banns pant bant panted banted panting banting pants bants pantry Bantry par baa pars baas par bah par bar pars bars pare bare paring bearing parings bearings park bark parked barked parking barking parks barks park barque parks barques parka barker parkas barkers parley barley parr baa parrs baas parr bah parr bar parrs bars parry Barry parse baas parse bars part Bart pass baas paste based paste baste pasted basted pastes bastes pasting basting pat bat pats bats patted batted patting batting patch batch patches batches pate bait pates baits path bath paths baths pathos bathos patten batten pattens battens patter batter pattered battered pattering battering patters batters pattern batten patterned battened patterning battening patterns battens patty batty Paul ball Paul bawl pause boars pause bores paw boar paws boars paw bore pawed bored paws bores pawed bawd pawed board pawl ball pawls balls pawl bawl pawls bawls pawn born pawn borne pax backs pay bey pays beys pay bay paid bayed paying baying PC BC pea B peas B's pea be pea bee peas bees peach beach peached beached peaches beaches peaching beaching peach beech peaches beeches peak beak peaks beaks pearly burly pearliest burliest pease bees pease B's peat beat peat beet peck beck pecks becks pee B pees B's pee be peeing being pee bee pees bees peed bead peek beak peeks beaks peep beep peeps beeps peer beer peers beers peer bier peers biers peered beard peeves beeves peg beg pegged begged pegging begging pegs begs peke beak pekes beaks pelt belt pelted belted pelting belting pelts belts pen ben pens bens pending bending penned bend penny Benny peoples Peebles per bur per burr perch birch perched birched perches birches perching birching peri beery peril beryl perils beryls perk burke perked burked perking burking perks burkes perry berry perry bury pert Bert Perth berth Perth birth pertly Birtley pest best pests bests pet bet petted betted petting betting pets bets Pete beat Pete beet peter beater peters beaters peter beta peters betas petty Betty pi buy pi by picker bicker pickers bickers pie buy pies buys pie by pieced beast pied bide pig big pike bike pikes bikes pile bile pill bill pills bills pillow billow pillowed billowed pillowing billowing pillows billows pin bin pins bins pined bind pinnacle binnacle pinnacles binnacles pious bias pique beak piques beaks pit bit pits bits pitch bitch pitched bitched pitches bitches pitching bitching plank blank planks blanks planned bland played blade plays blaze pleach bleach pleached bleached pleaches bleaches pleaching bleaching plead bleed pleading bleeding pleads bleeds pleat bleat pleated bleated pleating bleating pleats bleats pled bled plight blight plighted blighted plighting blighting plights blights plot blot plots blots plotted blotted plotter blotter plotters blotters plotting blotting ploughs blouse plume bloom plumed bloomed plumes blooms pluming blooming plunder blunder plundered blundered plunderer blunderer plunderers blunderers plundering blundering plunders blunders plush blush pocks box podded bodied poise boys polar bowler pole bole poles boles pollard bollard pollards bollards poll bowl polled bowled polling bowling polls bowls polled bold pollster bolster pollsters bolsters polony baloney pom bomb poms bombs pond bond ponds bonds pony bony pooh boo pool buhl Poona buna poor boor pop bob popping bobbing poppy bobby poppies bobbies porch bortsch pore boar pores boars pore bore pored bored pores bores poring boring pored bawd pored board pork balk porn born porn borne porridge borage port bought pose beaux pose bows posh Boche posh bosh posse bossy posses bosses post boast posted boasted posting boasting posts posts poster boaster posters boasters postern Boston pother bother pothers bothers pounce bounce pounced bounced pounces bounces pouncing bouncing pound bound pounded bounded pounding bounding pounds bounds pounder bounder pounders bounders pour boar pours boars pour bore poured bored pouring boring pours bores poured bawd poured board pout bout pouts bouts power bower powers bowers pox box praise braes praise brays praise braise praised braised praising braising praises braises pray brae pray bray prayed brayed praying braying prays brays prayed braid prawn brawn preach breach preached breached preaches breaches preaching breaching preach breech preaches breeches pressed breast prick brick pricked bricked pricking bricking pricks bricks pried bride pride bride prides brides prig brig prigs brigs prim brim primmed brimmed primming brimming prims brims prink brink prinks brinks prior briar priors briars prow brow prows brows prows browse Pru brew prude brewed prude brood prudes broods puck buck pucks bucks pudgy budgie puff buff puffed buffed puffing buffing puffs buffs pug bug pugs bugs pull bull pulls bulls pullet bullet pullets bullets pulley bully pulleys bullies pump bump pumped bumped pumping bumping pumps bumps pumpkin bumpkin pumpkins bumpkins pun bun puns buns punch bunch punched bunched punches bunches punching bunching punk bunk punks bunks punkah bunker punkahs bunkers punting bunting pup pub pups pubs purple burble purples burbles purr bur purrs burs purr burr purrs burrs purred bird pursed burst purser bursar pursers bursars pus bus push bush pushes bushes putsch butch putt but putt butt putted butted putter butter putting butting putts butts puttered buttered puttering buttering putters butters puttied butted pyre buyer pyres buyers rapid rabid repel rebel repelled rebelled repelling rebelling repels rebels rip rib ripping ribbing rope robe roped robed ropes robes roping robing rumple rumble rumpled rumbled rumples rumbles rumpling rumbling simple cymbal simples cymbals simple symbol simples symbols slap slab slop slob sop sob sopping sobbing staple stable stapled stabled staples stables stapling stabling sup sub supping subbing supper Sabah swap swab swapping swabbing swapped swabbed swaps swabs tap tab taper tabor tapers tabors tepee TB topi Toby tripe tribe tripes tribes tup tub unpacked unbacked