http://confirmtx.com/
https://www.btcspeedy.com
Not sure which of these are still currently working though, so definitely proceed with caution. Only used the Viabtc one in the past.
If your transaction is big enough, you can choose options whereas you pay them a fee to significantly increase your transaction speed.
Are you sure that btcspeedy is legit? Because honestly the site looks like it's been built on a $1 budget and not someone that would have links to the actual mining pool representatives that would accelerate transactions for them.
From my experience, confirmtx works fine. Also, if you go to the services section you'll see multiple people having threads offering free acceleration services. Simply reply with your txid and they'll accelerate it for you.