Any UK/EU equivalent of Robinhood (free trading, ISA support)?
They have trading accounts with ISA. It's not free but the fees for mutual funds, ETFs and most products are fairly reasonable.
However if you intend to do daily trading, I suggest you reconsider before you loose a lot of money. It's not that the fees are higher than the gains (they are), it's that it's very risky and good way to lose a lot of money.
They also offer an API they call Kite Connect [1].
Also, since they're not yet live I can't vouch for them, but here's an example: https://freetrade.io/