Omega DII / D2 lensboards (all round plates)
25mm hole (3) $6
30mm hole $6
32mm hole $6
Omega D5 / D6 lensboards and turrets
421-915 (unmarked) plate for 150mm EL Nikkor $50
421-056 flat plate 39mm threaded flange (3) $22
421-109 formed plate 39mm hole (black) $22
421-109 (unmarked) formed plate 39mm hole (silver with two mounting holes) (5) $20
421-108 (unmarked) flat plate 50mm thread (4) $15
421-108 (unmarked) flat plate 50mm thread (silver with two mounting holes) $12
421-115 (unmarked) flat plate 39mm hole (silver with two mounting holes) (2) $18
421-932 (unmarked) extended plate 39mm hole (silver with two mounting holes) (3) $18
421-932 (unmarked) extended plate 39mm hole (black) $22
421-932 extended plate 39mm hole (black, in box) (3) $22
421-943 flat plate 25mm hole $18
421-943 (unmarked) flat plate 25mm hole (older type with pebble finish) $10
421-930 (unmarked) extended plate 25mm hole (silver with two mounting holes) $17
404-867 three lens turret $30
404-867 three lens turret (thicker mount) $20
Omega B22 lenboards
flat plate 39mm hole $8
421-017 flat plate, 39mm hole $8
flat plate 32mm hole $8
Beseler 67 lensboards
standard 39mm flat plate with recessed area around mount (2, 1 in box) $10
Beseler 45 / 23c lensboards (4x4 square)
39mm hole $12
39mm hole (rougher shape, missing pilot light piece, can be taped over) $6
25mm hole $12
25mm hole with threads $15
39mm locking rings $5
39mm locking rings (heavy duty, marked Germany) $8
50mm locking rings $10
Also, if you haven't seen it, the following webpage is a great resource for figuring out what lens fits in what Omega mount.
http://www.khbphotografix.com/omega/LensMountD5.htm