There are many words that rhyme with "Saturday." Here are some examples from the search results:

• RhymeZone: kay, bay, brae, bray, cay, clay, day, dray, fay, fey, flay, fray, gay, gray, grey, hay, hey, jay, lay, lei, may, nay, neigh, pay, play, pray, prey, quay, ray, say, slay, spray, stay, stray, sway, they, tray, way, weigh

• WordHippo: flashily, manatee, nattily, pallidly, quackery, sanity, wackily, wrathfully, anarchy, basketry

• RhymeZone: bastardy, flatter me, flattered me, hattery, latterly, latterly, plattery, plattery, shattery, tattery

• WriteWithChorus: day, away, way, play, lay, say, pay, stay, bay, grey

• RapPad: Friday, Daddy, Buddy, Body, Shady, Bloody, Flurry, Furry, Marie, Scurry, Cd, Shorty

• WikiRhymer: battery, flattery, hattery, Slattery, yesterday, factory, olfactory, refractory, satisfactory, unsatisfactory

As we can see, there are many options to choose from depending on the context and desired rhyme scheme.