Depends what you want to define as a mod? Plenty of examples depending on how broad the categories are.
1. Electrical/electronic mods:
Game specific
IJ POA mod
TZ color changing door translite mod
and Generic
EL wire mods for ramps
Color changing shooter rods
2. Artwork mods:
Iron Monger decal as above
New and improved artwork - e.g The Shadow and Flintstones translites
3. Miscellaneous mods:
Powdercoating metal parts
Chroming/Gold plating metal parts
Installing mirror blades (aka No8 mirror polished stainless steel sheets)
Just my thoughts...
Would be handy to go to a dedicated page and look up your machine with a list of mods for that title.
There a lot of mods out there but all over the place. 
This might be the way to go.
One category that is machine specific for ease of reference.
and
one for generic mods which could cover most machines (mirror blades et al)
