avi, mkv, m4v for sure. Try others. If the built-in player does not play something, just installl free MX Player and it will play everything you throw at it.
Imagination is the only limit here.
OT MaxDB, CD1, CD5, J5, GD96, ME45, T68i, X6, CX65, A925, E398, MPx200, X6-2, OT715, D600E, W810, M600i, BB8100, W880, N95-2, P1i, Ignito, W880, X1, MS1, MS2, TP851, XT910, GTab 10.1, SGS3, SGS4, SGNote 10.1, Nexus 7 II