We used to go to other lifestyle glow events (check my profile pics - I believe those were from Glob Job circa 2018?). I used to wear white pants and shirts mostly with simple neon paint/glue on them. Amazon is great but considering the time, Michaels is a good bet at this point. They usually have a decent selection of neon glue/paint and likely some cheap shirts you could use. Even just neon shirts with sleeves cut off are better than nothing.

For her, anything neon. Wigs were always fun. Neon boas, neon boots, neon bikinis. Any way you can highlight her assets is always good. One year Mrs had a black wicked weasel bikini (small and thin) and wore white pasties underneath that really glowed (it was at a party that didn't allow nudity).

Side note to this all: If you go and like it, Hell, even if it's not your jam but you like being around other like-minded party people, I would recommend investing in a few costumes as glow event are likely going to become more and more popular again as people start getting out more. Go-Go boots, neon feather boas, neon hats, neon glasses, neon body paints, and even light up shoes are all good. At these events the goal is to be extravagant and part of the show.