Washers, marbles, spoons...anything metal or glass that's heavy and sanitized.
For my personal experiences, I find that pellets are better for shorter dry hops (3-7 days) because they release more oils in a quicker time frame. Leaf hops hold up to longer dryhop lengths without getting too harsh/vegetative.
Some people dryhop without mesh bags and instead wrap the nylon bag around the racking cane to avoid trub. You may get slightly less surface area contact if using leaf hops with this method since they mostly float on the surface. But pellets tend to sink after awhile, which is why I don't bag them.