9-Hole Reviews, Josh and Henry’s channel, is one of my absolute favorites on YouTube for the simple fact that they are very good at showing data. They’ve set up a several avenues to show data on firearms and firearm accessories that convey that data in an entertaining manner. They also present interesting thought exercises in their VS. series which go into scenarios where there isn’t a right answer, just one that you must justify. If you can, you are right. If someone disagrees and can justify there answer, they are also right. It is the lack of a logical and justifiable thought process that makes an answer wrong, not the selection.
In that regard lights have exploded (pun intended, for those who know) in popularity as their utility is becoming more widely known. We are far beyond the days where a weapon light was for the SWAT teams only. There are dozens of good options on the market for rifle and handgun lights now, with more coming.
Many are covered in this video, others are not. Some can be extrapolated from the video, such as the TLR-7 also matching performance with the 7A and RM1 models from Streamlight (all of which are lights I like under the right circumstances).
If you want my opinion on the lights to look at for carbines, skip to 19:38. They cover four, including my two preferred. But remember that having a different light, or an older light, than what is currently that cutting edge of the market doesn’t make it a poor choice. If the light is reliable and fills the need (say, illuminates all rooms of your house properly and allow you to see into rooms you are pushing into)
If you’re looking at lights for pistols, TLR-1 HL, X300U A/B, TLR-7A (if needs a smaller light). Modlite PL350 once it drops, rocking the PLHv2 head. If I were to pick the proverbial “can have only one” of lights it would be PLHv2 on compatible bodies.