Rhythm: Metronome

Instead of playing to a click on 1, 2, 3 and 4, you can interpret the clicks of the metronome as various positions in the bar. This is a great exercise to improve your sense of time. You can practice any exercise or song using these. Especially soloing on sparse or crossing metronome settings is an invaluable exercise.

Displacement
The metronome is playing four beats per bar, but you interpret them as offbeats, sixteenth offbeats, second notes of a triplet etc.
Displacement
Reduction Within Bar
The metronome is only playing one or two clicks per bar. To make this more difficult, you can interpret the remaining clicks as offbeats or similar, like in the previous exercise.
Reduction Within Bar
Reduction Within Form
Use a drum machine or app to play a beat only every other bar. Then every three, four, five bars and so on. Then do the same, but with only one beat playing or with the beat displaced.
Reduction Within Form
Cross Rhythms
Interpret the metronome as a steady cross rhythm. If you want to go even further, try reducing the rhythms.
Cross Rhythms
Odd Meter Against Even Metronome
This is a great way to make your odd time playing steadier. The easier version results in two different bars, the more difficult version results in four different bars. To make this harder, try to combine this with the other methods.
Odd Meter Against Even Metronome