I hope this isn't reverse-Delboy, it's just that seeing someone get a Microkorg for £160 this way still haunts me... Anyway:
Line 6 Verbzilla
Boss CS-3 Compression Sustainer (or similiar/better; suggestions welcome, but my budget probably stretches as far as an MXR Dyna Comp)
Any cheap mixer (doesn't have to be fully working, just enough to make a fun no-input desk)
That's all I'm specifically hoping to find second hand, but on the off-chance that anyone has grown tired of their Monome/NanoKontrol/NanoKey/LSDJ+MIDI interface/DS-10/R4DS+GlitchDS etc. any of those would be lovely as well! Pedals, synths, unusual instruments, percussion instruments, toys ripe for circuit-bending, anything electronic, anything fun. If you're reading this in the hope of selling something you might as well PM me - I don't expect to find everything I'm after, so I'll probably have some cash left for anything interesting.
Eagerly awaiting any PMs. :D