If you are looking for some good skirmish, and/or even larger gaming scenario ideas for Eastern Ukraine, and/or other low-intensity conflicts, this page is an excellent resource for that:
link
There's a lot of mortar, rocket, and artillery barrages that seem to occur on a fairly regular basis, but sometimes, these can springboard into combined arms affairs with a squad or two of troops, to many more than that, and a handful of vehicles, to the occasional company or more of them engaged in a desperate battle for terrain, or regional dominance.
The page above gives a good, high level, synopsis of the types of forces involved in the battles and skirmishes, but leaves you free to determine the actual number of forces and types of units involved on both sides, in many cases.
15mm troops and vehicles would be a natural for these types of small battles, in many cases, but you can also use some of the new 1/144th scale (12mm) troops and vehicles available from various companies now, like Timecast, Minifigs, and others too.
Pitting Soviet/Russian troops against Ukrainian troops with the same vehicles and weapons in many cases, means you can get more bang from your hobby buck, and levels the playing field a bit too, since in most cases, the forces are very similarly armed. The Russian-backed guerrillas do seem to have the advantage in terms of overall numbers and artillery, mortar, rocket ammo, and aerial drones though.