1 Syllable: S
ab, act, ad, adds, ads, aft, app, apt, ash, ask, asp, ass, ast, at, ax, axe, back, bad, bag, bask, basque, bass, bast, bat, batch, bats, black, blast, brag, bras, cab, cache, cad, calf, cap, capped, caps, capt, cas, cash, cask, cass, cast, caste, casts, cat, catch, cats, chaff, chap, chat, clad, clap, clapped, clash, clasp, class, crab, crabbed, crabs, crack, craft, crag, crash, crass, dab, dad, das, dash, dat, drab, draft, drag, dragged, drags, draught, fac, fact, fad, fag, fast, fat, fax, flag, flagged, flags, flap, flapped, flaps, flash, flask, flat, flax, gad, gag, gap, gas, gash, gasp, glad, glass, gnat, grab, grabbed, graf, graft, graph, grasp, grass, hack, had, hadst, hag, half, hap, hash, hast, hat, hatch, hats, jack, jacques, jagged, jas, katz, kept, knack, knapp, lab, lac, lack, lad, lag, lagged, lags, lap, lapped, laps, lapse, lash, lass, last, lat, latch, laugh, lax, mac, mack, mad, mag, mak, map, mapped, maps, mash, mask, mass, masse, mast, mat, match, mats, matt, max, nad, nag, nap, nash, nat, pack, pact, pad, pap, pass, past, pat, patch, pax, plaid, plaque, plat, platt, prac, pratt, quack, rack, raft, rag, rap, rapped, rapt, ras, rash, rat, sac, sachs, sack, sacs, sad, sag, sap, sapped, sash, sat, saxe, scat, scrap, scratch, shack, shad, shaft, slab, slack, slag, slap, slapped, slash, smack, smash, snack, snap, snapped, snaps, snatch, spat, splash, stab, stabbed, stabs, stack, staff, stag, stat, strap, strapped, straps, tab, tack, tact, tad, taft, tag, tagged, tags, tak, tap, tapped, taps, task, tat, tax, that, thatch, that's, thrash, track, tract, trap, trapped, traps, trash, vas, vast, vat, wag, wax, wrap, wrapped, wrapt, zag
2 Syllables: SU
2 Syllables: US
3 Syllables: UUS

Found 330 words across 4 groupings. Skipped 124 excess words of a similar stem.