I run one at my work, so I know it's legit. It started with me and a coworker I shared my office with, then it expanded from there and now has 12 members. All money goes to buy a mix of Powerball and Louisiana Lotto tickets. I collect $4/each from the members every 2 weeks on payday, and buy a mix of numbers the members selected in quickpicks on multidraw tickets that cover all 4 drawings until the next payday. I go the multidraw route so I don't have to keep running to the store to buy tickets. We haven't won any big prizes yet, but we have hopes. The most we've won is $52, which of course went into more tickets.
When the Louisiana Lottery held its Millionaire Raffle game, I took a vote of the membership and the majority agreed to buy one ticket with the winnings just to try something different. It didn't win, but it was fun to try. When we won the $52 total, I polled the members to see if they wanted more tickets or cash, or something else, they of course voted more tickets.
If you can't find one, start your own but let me tell you, it takes work to run a good honest pool, and that is what I do. I've tried to keep it small, but others find out and want to join. I originally planned for it to be just members of my department, but others found out and got involved.
I hope this helps. I wouldn't ever do a pool with strangers online, mainly because I don't know if I'll ever see the money.
Good luck.