Several companies ply the streets of Pattaya and Jomtien to take you to Bangkok, Victory monument to be precise, actually they only drive down Sukhumvit Road but it is a quick cheap way to get to Bangkok, takes about 2 hours and haven't been on one where the driver is a drugged up yaba addict.
We catch the one from Sattahip as it stops at the end of Soi Thepprasit, ok costs 140baht when we could catch one from central Pattaya for just under 100baht but it's not worth the savings to us.
At the Petronas petrol station just past Pattaya Klang / Central Pattaya Road is the booth to buy your ticket to Bangkok and where you catch the minibus, can't miss the petrol station as it is a large one, also has buses inside to Nong Khai etc.
This is our Sattahip to bangkok minibus, pretty much the same as all the others.
Victory monument has loads of minibus places round it, this one pretty much covers the whole of Thailand with its minibuses, ie from Hua Hin to Hat Yai or more popular tourist destinations as Phuket and Krabi.
More options on getting to Bangkok from Pattaya https://teakdoor.com/view.php?pg=pattaya_getting_around