[Matty22]

I tend to get into the same rut a bit. What i do is pick a key, and play around with it.
I use C a lot, easy chords, and they sound good played as barres up the neck which i find adds spice to play an Am at thr 5th fret instead of open.

Another thing, to just add colour to the chords your using, is play with some suspended chords. Dsus4/sus2 type of thing. I sometimes pic a song with chords i dont use very often, just to remind myself they are there... Maybe picking some chords say A E D and just play around with them and see if you can comeup with something... Or adding little runs here and there like a-2-3-2-0 kinda thing....