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, Pratt, 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, 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.