1 Syllable: S
ab, act, ad, adds, ads, aft, app, apt, ask, asp, ast, at, ax, axe, back, bad, bag, bask, basque, bast, bat, black, blast, brag, cab, cad, cap, capped, caps, capt, cask, cast, caste, casts, cat, chap, chat, clad, clap, clapped, clashed, clasp, classed, crab, crabbed, crabs, crack, craft, crag, crashed, dab, dad, dashed, dat, drab, draft, drag, dragged, drags, draught, fac, fact, fad, fag, fast, fat, fax, flag, flagged, flags, flap, flapped, flaps, flashed, flask, flat, flax, gad, gag, gap, gasp, glad, gnat, grab, grabbed, graft, grasp, hack, had, hadst, hag, hap, hast, hat, hatched, hats, jack, jacques, jagged, katz, kept, knack, knapp, lab, lac, lack, lad, lag, lagged, lags, lap, lapped, laps, lapse, lashed, last, lat, laughed, lax, mac, mack, mad, mag, mak, map, mapped, maps, mashed, mask, massed, mast, mat, matched, mats, matt, max, nad, nag, nap, nat, pack, pact, pad, pap, passed, past, pat, patched, pax, plaid, plaque, plat, platt, prac, quack, rack, raft, rag, rap, rapped, rapt, rat, sac, sachs, sack, sacs, sad, sag, sap, sapped, sat, saxe, scat, scrap, scratched, shack, shad, shaft, slab, slack, slag, slap, slapped, slashed, smack, smashed, snack, snap, snapped, snaps, snatched, spat, splashed, stab, stabbed, stabs, stack, staffed, stag, stat, strap, strapped, straps, tab, tack, tact, tad, taft, tag, tagged, tags, tak, tap, tapped, taps, task, tat, tax, that, thatched, that's, thrashed, track, tract, trap, trapped, traps, vast, vat, wag, wax, wrap, wrapped, wraps, wrapt, zag
2 Syllables: SU
2 Syllables: US
3 Syllables: UUS

Found 290 words across 4 groupings. Skipped 95 excess words of a similar stem.