Diana K

I have used plant trimmings that I think are Crape Myrtle. Very hard wood, no tannins. I do know plant material rather well, and am 90% sure it is Lagerstroemia indica or Lagerstoremia hybrid. Both species are grown around here a lot, and it is entirely possible for someone to prune then dump in the neighbor's field.

Daniil

In my new set up I am using Western Hemlock roots. The tree was blown down about 15 years ago and roots never touched water, except rain. I soaked them for two month and then boiled for 4-5 hours in metal trash can in the back yard fire pit. The water in the aquarium is clear from day one, no tannins or toxins.
So, from my experience, soaking and boiling Western Hemlock roots, they are very good wood for the aquascape.

chadly

One that I know has not been mentioned is corkscrew willow or contorted willow branches. I've used them in my aquariums and have collected them from my back yard. They have a skin on them that you'll want to clean off. They will sink over time. I like to use the smaller end branches. They have a nice curly shape that resembles root structures, or use them for bare hardscape accents.

Tex Gal

Post #1 list has been updated to include all woods from this point backward.

jestep

Another is mangrove roots and branches.