Pace Chainring - Probably not many of these left.

[Woz]

Not mine, rather unique chain bed pattern and must have been expensive BITD.

https://www.ebay.co.uk/itm/326199520148

 

[Supratada]

Ah yes. the extruder groove. I remember it well, in fact its still on my bike. Can't say I know if it worked better than a normal, but I don't recall having any mud issues.

 

[M-Power]

I have one of these FS low miles in 44T think its 110 BCD