Almost all paints of all colors and even dyed fabrics reflect IR, the challenge is to find those that don’t for contrast.
But as Meierhans suggested you can use “safety” reflective tapes and fabrics (a web search will turn up lots) that have very high gain for light near the viewer. You can use a ringlight, but I’ve found any IR source next to the camera works well unless the camera is very close to the object (the lens-to-light distance is a large fraction of the lens-to-object distance). The 3M brand name is “Scotchlite”, but there are many around. Here in the US every car parts store has reflective tapes, and the fabrics can be ordered online.
Tip: you can make almost invisible fiducials by using normal black paint (which is usually very IR reflective) and an IR absorbing black paint.
Tip #2: Plug your IR cam into your laptop and go to the paint/fabric store.
Here’s a pic with an IR-modified PS3Eye where the dancers have the safety reflective fabric woven into their costumes, with a standard 100W tungsten clamp light (with RGB gels to block the visible light) next to the camera. Even with the stage being lit with tungsten stage lighting the fabric is such high gain it still reads easily:
