Here is the penultimate set of SOWPODS four letter word anagrams:
Seven Anagrams
OWTS/STOW/SWOT/TOWS/TWOS/WOST/WOTS
Six Anagrams
OPTS/POST/POTS/SPOT/STOP/TOPS
RUES/RUSE/SUER/SURE/URES/USER
Five Anagrams
OAST/OATS/STOA/TAOS/TOSA
ORTS/ROST/ROTS/SORT/TORS
PART/PRAT/RAPT/TARP/TRAP
PAWS/SPAW/SWAP/WAPS/WASP
PEST/PETS/SEPT/SPET/STEP
RIOT/ROTI/TIRO/TORI/TRIO
Four Anagrams
OARS/OSAR/SOAR/SORA
OHOS/OOHS/SHOO/SOHO
OILS/SILO/SOIL/SOLI
OWER/OWRE/WERO/WORE
PARS/RAPS/RASP/SPAR
PATE/PEAT/TAPE/TEPA
PAYS/PYAS/SPAY/YAPS
PIES/PISE/SIPE/SPIE
PORY/PYRO/ROPY/YORP
POWS/SOWP/SWOP/WOPS
RATO/ROTA/TARO/TORA
RITE/TIER/TIRE/TRIE
RYOT/TORY/TROY/TYRO
Three Anagrams
ODYL/OLDY/YOLD
OKES/SKEO/SOKE
ONOS/OONS/SOON
ONST/SNOT/TONS
ONTO/OONT/TOON
OOPS/POOS/SOOP
OPUS/OUPS/SOUP
OUST/OUTS/SOUT
OWES/OWSE/WOES
PATU/TAPU/UPTA
PEER/PERE/PREE
PEIN/PENI/PINE
PEPO/POEP/POPE
PERI/PIER/RIPE
PERP/PREP/REPP
PIRS/RIPS/RISP
PISS/PSIS/SIPS
PITS/SPIT/TIPS
POET/POTE/TOPE
POOR/PROO/ROOP
PORE/REPO/ROPE
PREY/PYRE/RYPE
PUMY/UMPY/YUMP
PURS/SPUR/URPS
PUYS/UPSY/YUPS
RETE/TEER/TREE
RIVE/VIER/VIRE
RONT/TORN/TRON
ROOT/ROTO/TORO
ROWT/TROW/WORT
RUDS/SURD/URDS
RUSA/SURA/URSA
SAUT/TAUS/UTAS
SITE/STIE/TIES
STOT/TOST/TOTS
SUIT/TUIS/UTIS
SWAY/WAYS/YAWS
TAVS/VAST/VATS
TAWT/TWAT/WATT
TEDY/TYDE/TYED
TWAE/WATE/WETA
VAIL/VALI/VIAL
WAKE/WEAK/WEKA
Two Anagrams
OAFS/SOFA
OBEY/YEBO
OCAS/SOCA
OMBU/UMBO
ONER/RONE
OOFY/YOOF
OOTS/SOOT
OPPO/POOP
ORAD/ROAD
ORRA/ROAR
OTTO/TOOT
OUKS/SOUK
OURS/SOUR
OVAL/VOLA
OVER/ROVE
OWLY/YOWL
OYER/YORE
PADI/PAID
PAIK/PIKA
PAIS/PIAS
PALP/PLAP
PALY/PLAY
PATH/PHAT
PATY/PYAT
PAUL/PULA
PEDS/SPED
PEES/SEEP
PERM/PREM
PEWS/SPEW
PHOT/TOPH
PICS/SPIC
PINY/PYIN
PISO/POIS
PLOT/POLT
PLOY/POLY
PLUE/PULE
PLUS/PULS
POOT/TOPO
PORT/TROP
POSS/SOPS
POUR/ROUP
PRAM/RAMP
PRAO/PROA
PROM/ROMP
PRYS/SPRY
PUER/PURE
PUIR/PURI
PUNS/SPUN
PURR/RURP
PUSS/SUPS
PUTS/TUPS
PYET/TYPE
PYOT/TYPO
QADI/QAID
RAHS/RASH
RAIK/RAKI
RAKE/REAK
RANT/TARN
RARE/REAR
RATA/TARA
RAWN/WARN
RAWS/WARS
RAYA/YAAR
REEK/REKE
REFS/SERF
REIN/RINE
RENT/TERN
REVS/VERS
RHUS/RUSH
RIPT/TRIP
RITS/STIR
RIVA/VAIR
ROKY/YORK
RORT/TORR
ROTE/TORE
ROUT/TOUR
RUMS/SMUR
RUNT/TURN
RUST/RUTS
RYKE/YERK
No Anagrams
OARY OATH OBES OBIA OBOE OCCY ODAH ODEA ODIC OFAY OFFS OGAM OGEE OHIA OILY OLEO OLIO OLLA OMOV ONIE ONLY ONYX OOFS OOSE OOSY OOZE OOZY OPAH OPAL ORAL ORBY ORYX ORZO OSES OSSA OULK OUMA OUPA OUPH OURN OUZO OVEN OVUM OWED OXER OXES OXID OXIM OYES OYEZ PACK PACT PACY PAIR PALL PAND PANG PANT PAPA PAPE PARK PARP PARR PAUA PAVE PAVS PAWA PAWK PAWL PAWN PEAK PEBA PECH PECK PEEP PEGH PEGS PELF PELL PEND PENK PENT PEPS PERK PERN PERT PERV PFFT PFUI PHEW PHIZ PHOH PHON PHUT PICK PIED PIET PIKI PILI PILL PILY PIMA PIMP PING PINK PINT PION PIOY PIPA PIPE PIPI PIPS PIPY PIRL PIRN PITA PITY PIUM PIXY PIZE PLAN PLAT PLEB PLED PLEW PLEX PLOD PLOP POCK POGY POKE POKY POLK POLL POMP POND PONG PONS PONT PONY POOD POOF POOK POPS PORK PORN POSY POTT POUF POUK POUT POWN POXY POZZ PRAU PRAY PREX PREZ PRIM PROB PROF PROP PROS PROW PRUH PSST PTUI PUBE PUBS PUCE PUCK PUDU PUFF PUGH PUKA PUKE PUKU PULI PULK PULL PULP PULU PULY PUMA PUMP PUNA PUNG PUNK PUNT PUNY PUPA PUPS PUPU PURL PUTT PUTZ PYIC PYNE QATS QOPH QUAD QUAG QUAI QUAT QUAY QUEP QUEY QUID QUIM QUIN QUIP QUIT QUIZ QUOD QUOP RACA RAFF RAGG RAKU RARK RATU RAUN RAZE RAZZ REBS RECK RECS REDD REDS REMS RENY REPS REWS RICH RICK RICY RIDS RIFF RILL RIND RINS RIPP RITT RITZ RIVO ROAN ROCH ROJI ROLL RONG ROOF ROON ROOS RORE RORY ROSY ROTL ROUM ROUX ROWS RUBE RUCK RUDD RUER RUFF RUIN RUKH RULY RUMP RUNE RURU RUSK RYES RYFE RYND