I have mine on top of a four square Ikea Kallax unit
It's a good height for a cage with a front opening door - just right. And you have storage underneath. The cage is slightly bigger all round than the Kallax unit so there is very slight overhang but the feet from the cage base fit on. It can slide about too easily so I put a hemp mat underneath it and that keeps it secure.
Comes in various colours - I got mine second hand for £10
KALLAX white stained oak effect, Shelving unit, 77x77 cm - IKEA