I was wondering if any paysite owners had any suggestions on what to use as niche specific upsells that arent 'adult' in nature per se?

For example, an officewear store in a suit/tie fetish site, foreskin restoration products on an uncut site, etc, etc?

Has anyone found any good non-adult upsells that work well on niche specific traffic sources like the two examples i posted above and if so, what were they and on what niche?

Regards,

Lee