Hi there and welcome!
Ok here's the skinny on pellets.
Most brands are list a "type" of wood on the bag like "Hickory". What you get is usually about 20-35% of Hickory and then the rest is a more plentiful hardwood like Oak or Alder or sometimes Maple.
The good thing is that any hardwood or fruit wood is safe and perfectly fine for smoking. The bad news about these brands is that you don't actually get what you think u are getting :(
Unsafe pellets would potentially be those for "wood stoves" where they may be all kinds of stuff. You don't really see these unless u go out of your way online to get some "stove" pellets.
Next that is not really unsafe but seems to be viewed as being shady, would be the Traeger pellets. At one point in time they used a cheap plentiful hardwood like oak or alder and then used "flavoring oils" to give you the flavors for stuff like Hickory or Apple.... What are the oils? I have no clue. I don't know if they still do it but people seem to think they do and the fact that
they ever did it makes me avoid them period.
Now the BEST brand of pellets in my opinion is Lumberjack brand. This brand gives you 100% of the wood listed on the bag. So if you buy Hickory u get 100% hickory and so one. They also CLEARLY identify on the label if you are getting a blend like "Fruit Wood Blend" or "Competiation Blend", or "Mesqutie Blend", etc.
The other exceptional brand is Cookin Pellets brand. They follow the same practice that Lumberjack does but the difference is they only have like 2-3 offerings total where LumberJack has a ton of 100% options.
Also, I believe Cabela's brand and even the
A-Maze-N brand are both rebranded Lumberjack pellets so those seem to be good to go.
Honestly with a pellet smoker, for heat generation I would burn
Pit Boss pellets you get from walmart since they are cheap and are perfectly fine wood pellets but they do the whole hidden blend thing. Now I would use an
A-Maze-N Pellet Smoker (AMPNS) tube and load it with Lumberjack pellets and burn it for my pure flavor smoke.
This way the cheap pellets burn for heat/fuel and the good Lumberjack pellets burn for flavor.
You maximize your productivity and flavor while minimizing your cost this way :)
I hope this helps for pellet info! :)