If you don’t carry it with you, in general, look up. It is best if you can practice looking for dry material when you don’t need it, so when you do need it you can avoid traipsing around getting wet trying to find DRY tinder!
Look up the side of a large tree, often you can find some dry sections of the tree that may have moss and bark that can be shaved for tinder. Flake off a bit of the outer layer of the bark to get to some dry stuff under it. Then you can look in the shelter of the same tree on the ground. Move stuff around, lift a layer of the material under a tree, or a rock under the same tree. My faves are pine and fir…sometimes the duff will stay dry all year.
Look under the cut-bank of a creek. If there is a good overhang you can often find lots of dry material under there. Moss, leaves, small sticks and lots of dead dry roots (very fine) that all burn well.
+1 on the mature cattails. Love those things. You would be surprised how long they stay dry, even in the wettest weather. You can actually often times see the water bead up on them. (In December in north Idaho, me and a buddy shook about 4 of them loose over a cattle pond. it was raining lightly at the time, and with 1 spark from a bic the whole thing burned across the entire pond in a beautiful wave that lasted about 2 seconds. What a blast of heat! You need to re-pack then together again if you want to actually start a fire rather than a slow explosion.)
Mullein plant. Even well into winter you can often find dry material in a patch of mullein. If it all seems to be wet (don’t forget to check the base) split it open and check the center. Not to mention you would be doing everyone a favor by destroying it
Birch trees. Of course you can peel off some birch park and usually find something dry enough to scrape/shred into tender
Cut/damaged trees +1 for sap. Granted, getting it to light by spark is not easy, but MAN, DOES IT BURN! Examine the injury and see if you can pull off some small bits of dry wood in that area, if it is soaked with sap all the better if you can shave it and it will act like “fatwood”
Pull the bark off a downed tree…inspect all the way around the tree for dry material.
Clumps of grass. Dig down deep, see if you can find something dry.
Treat large
Sage /antelope/bitter brush plants like trees. their bark will often flake off to reveal some dry material without damaging the plant, much the same as the pine and fir and birch.
Split open some elderberry…
Milkweed. I think it was mentioned, but worth it again. In Idaho we had one we called milkweed, but I think it is actually
Goat's Beard Thistle...