If the mini you have has an open hand, you could get a reaper flaming sphere and glue(plastic main mini) or green stuff (metal) on the sphere, I got my spheres in a pack of three from a third party, and they are big, so there may be balance issues if you use a lighter main mini. The spheres are translucent red and paintable.
I got home and realized the sphere is way too big for that, but you could cut off the wisp of fire at the top. Also, if you don't mind cutting up a different mini, the red wizard mini from the new dnd icons booster set has great magic hands, might be able to snag one for an ok price on ebay. Looking at the red wiz I have,.his right hand looks like it could pop off, and with a good glue, no need to repaint. On a side note, I do not recommended buying a booster for that icons line, especially for pc minis, imo there are only two good and one exceptional pc minis in the set, and the red wiz is the standout.'ll