This is one cool spider. It is commonly called the oil-can spider. Take a close look at the body and you will see why they are called this. They are not common in Dominican amber (although I would not say they are rare). There is a little confusion in terminology of this genus: it is either Lasaeola or Dipoena (family Theridiidae). The amber is small and thin.
Homoptera, Fulgoroidea - there are 2 planthoppers in this piece of Dominican amber. One planthopper is very small. In fact the small one looks as though there is a mite on one of the back legs (but upon further inspection, it is not a mite)- really cool. Finally there is a large springtail, Collembola (not shown in pictures).