This was another type on the mixed round. It seems that “knapp daneben” almost works better for checkered fillominos than for the plain ones.
Rules Add or subtract 1 from each clue, then solve as a standard Checkered Fillomino.
Another break, this time for the series of Kellers. This one didn’t come out quite the way I wanted and could use a bit of polishing, but…
Rules Split the grid into areas of size 1, 2, 3 such that areas of equal size don’t touch along an edge, and such that any given number is contained in an area of that size. (I.e., Fillomino with areas of size at most 3.)
Here’s a Checkered Fillomino, flowery theme.
Today marks the start of a series of Checkered Fillominos on croco-puzzle, check them out! (Solving on time will require making an account; they become freely playable after one week. No Java required.)
Here’s an extra one; the croco series starts out a bit more gently than this.
Here’s a fractional fillomino. Please excuse the lazy rendering, I don’t expect to make more of these.
Rules Subdivide the grid into areas. Numbers within an area must equal the size (in unit squares) of that area. Areas of the same size must not touch along an edge.
Two more Checkered Fillominos. I made a bunch of them for the 24 hours that take place in Budapest this weekend. These here use some different logic. The first one turned out to have an easier break-in that circumvents what I had in mind, but maybe the similarities help as a hint?
The German qualification is through. The puzzles will be available there again sooner or later, maybe I’ll post my contribution to the set here later. Here’s a somewhat trickier Checkered Fillomino that didn’t make it. I’m not sure it’s right to tag it as hard, that depends a lot on how well you know the type. 
This variation was introduced by Nikolai Beluhov at Puzzled by Titles, see the authoritative rules and two very tricky puzzles: Fillomino 6: Checkered, Fillomino 8: Checkered. Here’s something that’s hopefully both correct and a little more approachable.
Rules (brief): Solve as a standard Fillomino, and shade some resulting polyominoes, such that no two shaded or unshaded polyominoes share an edge.
Maybe Puzzles 