I have 2 sets of the iconic combiners - G1. Still working on getting a complete second set for Computron though. I like to display them in combined mode 1 set, then the other set in individual bot mode. I still haven't opened my Reissue Predaking for this, also haven't really opened 3 of 4 of my Kreon Combiners, but I have to rearrange my Kreon display to accommodate the combiners . Ive only taken out Bruticus Kreon and he's on gestalt mode on display.
G1 decepticon combiner shelf

Gi autobot combiner shelf

For G2 I keep them in individual bot modes. There's enough space for that anyways, for now.
Most recently completed a second set of Monstructor - got Bristleback cheap at the last Parra fair heheheh

except for Liokaiser which I only have 1 set, I have these in bot individual mode, I didn't wanna fiddle with them as they're pretty expensive and some fig suffer from GPS so if I ever do come across an extra set I can afford then Ill put that in combined mode.

my BW combiners are in their combined mode to save space as there's a lot of kibble going on with BW figs. But I keep Magmatron in separate beast modes rather than in combined beast mode.

RiD combiners in individual bot mode
Energon/ROTF combiners ( same mold) - in combiner mode to save space, also the newer repaint in ROTF are fitted with the 3rd party upgrades so they're always going to be in combined mode instead.
Wanted AM partner Vanguard, Myclones Dirge, G1 Victory Leo, e-hobby Dark scream ( the black version), e-hobby Magnificus
Parts- AM partner Basher-side guns, G1 Actionmaster Elite Windmill's blades[I][B]