Green’s Dictionary of Slang

something which the speaker cannot precisely name.

1960		G.W. Target Teachers (1962) 188: We were on the same Emergency Training what-have-you just after the War.
1979		W.D. Myers The Young Landlords 137: [T]hey went through their little number about giving each other five and bumping hips and what have you.
1982		W.D. Myers Won’t Know Till I Get There 55: ‘You have enough money for vacations and sports equipment and what-have-you’.
2024		J. Meades Empty Wigs (t/s) 513: ‘That building... it was full of dungeons... chains and what have you...’.