The Lumintop FW3A is the result of two years of development on enthusiast forums BLF and TLF. It's one of the smallest 18650 flashlights, with three emitters, a tail e-switch, an open source firmware, and a firestarting 2800+ lumen burst mode. It already offers four LED options, with more to come, has great ergonomics, a fantastic user intefrace, optics that are nearly as easy to change as the battery, and no glue anywhere. Did I mention it's under $40? It's under $40.

Wowtac is a budget brand affiliated with Thrunite offering a line of 18650-powered flashlights, with an included 18650 battery that has a direct USB charging port, starting at $20. The A2S is the right-angle/headlamp version with higher output and a larger battery capacity for $30. This is probably the best value headlamp on the market and also makes a good handheld.