Each row and column must contain the digits 1-9 once
Killer cages create irregularly shaped regions within which digits can not repeat
Thermometers increase from the bulb end
Kropki and XV rules apply including the negative constraint. So no adjacent digits are consecutive or in a ratio of 1:2 or sum to 5 or 10.
Links to play online:
F-Puzzles without solution checking
F-Puzzles with solution checking, but includes ugly 1x9 regions that are the same as the rows so the software can understand it
Penpa+
This is my first puzzle. Curiously, it is possible to remove all but one of the cages and convert the given digit into another stubby thermometer and my computer says it still has a unique solution.
F-Puzzles minimal But it would not be ‘approachable’ by a human.