There is huge variety of bushes. A list of commonly used bushes is displayed here.
Round bushes are hardened & ground.
Where as oval bushes are broached finished ground & nitrided for surface hardening.

COLLAR ROUND BUSH ID X OD X LENGTH –
1] 19 x 25.4 x 25 L
2] 19 x 30 x 31 L
3] 22 x 32 x 38 L
4] 25 x 35 x 31 L
5] 30 x 38 x 44 L
6] 32 x 45 x 45 L
7] 35 x 45 x 21 L
COLLAR OVAL BUSH A/C F X OD X LENGTH –
1] 19 F x 25.4 x 25 L
2] 19 F x 30 x 31 L
3] 21F x 38 x 31 L
4] 25 F x 45 x 31 L
5] 25.4 F x 40 x 36 L
6] 30 F x 45 x 45 L
7] 32F x 45 x 45 L
All dim are in mm.