I have a old bushnell tracker light that runs on a single AA has a white light mode (125 or 150 lumens, I think), a red LED to help preserve night vision and not alarm animals and a LED tracking mode. This light is nice and light and compact making it easy to carry and it is very versatile, though I don't know if they are still making these. One thing I don't like about the LED blood trackers is that while it causes red to stand out, it also turns yellow into a bright orange that can be confused with red. These LEDs also cause blue to pop out, but this is less of an issue because blue is not generally common in the woods. These blood tracking lights only work by color there is nothing magical about these lights to make blood stand out other than the red color of fresh blood - they will not work on darkened/dry blood. And sometimes a white light will work better, depending on the conditions.
I also made my own tracker light out of a 2D incandescent Maglite - I used a a couple of 3 AA to D cell series adapters to raise the Voltage so that I could run a 6 Cell xenon bulb and I installed a blue lens filter (blue filters only work with incandescent bulbs, with LEDs you need mixture of blue or green and red for blood tracking). This is more selective of the colors that stand out, everything looks blue or black except for red and blaze orange that stand out.
Primos makes some LED tracker lights that are supposed to be good, though I have never used them.