Do you mean funding opportunities or lab opportunities?
Funding opportunities often depend on what you will be working on, although there are several many student funding opportunities, which your school should be able to point you towards. The AOA and Valentine Mott one's come to mind. I did the AOA one between M1/M2 and it was great ($5000 stipend + $1000 to present). Start now, though, because the deadlines for these tend to be in early Jan.
There are some formal research program (Vandy I know has one), but you're best bet without those it to just cold call/email people you would like to work with. Or, better yet, have an attending/dean at your school introduce you. Not everyone will bite on a cold email, but maybe 20% will, so keep your options open. I got 2 research gigs at top-notch places by a cold email.