Well I've surveyed the battlefield... this is what I've found:
APC SmartUPS 1000
APC SmartUPS 1400
APC Backups RS 800
smartups sc 1000
MGE Pulsar Evolution 2200
I wonder

I would either fix or use the transformers and heatsinks.
Those look like higher voltage units (24V+). I have an APC 700 which is 24V.
Even so, sometimes one will find a transformer with 6 x 6V windings in a 12V UPS.
Transformers with 4 x 6V are more common but still useful IMO.