Guess it would be the following in no particular order, 10mm, 357, 41mag, 44mag, 45 Colt, 454C, 7 Mag and 7mm STW.
I load for everything we shoot but those give me the sincere satisfaction of availability, economy, and accuracy. Just a quick stroll down any stretch of ammo at the LGS usually puts a smile on my face looking at the prices of any factory offerings in those calibers IF they are even available.
As most know some calibers are best used as a handloaders option anyway, and it's nice to be able to cobble your own full tilt boogie ammo that meets or exceeds the comparable factory equivalent performance.