Yeah, similar names being included expands the possibilities, but I'm thinking that you have to set a limit on the parameters of your search to not include any old well with a similar sounding name.

So we have black well, goblin well, and dead well to work with.

A lot of black wells were connected with druids, the church seeing black as an evil colour and the druids as evil. Then again, a well of the dead, which is the other name of some black wells, are actually celtic burial shaft wells. Druid wells often became "rude" wells over time, or christianised as "well of the (black) rood". If you start including these possibilities, there is the rood well near east linton as a consideration. I'm not as familiar with landmarks out of the lowlands where I grew up to know offhand if other possibilities are opened by looking at it this way.