Memrise/ quizlet/ anki for vocab
Lawless French is good if you need explanations to certain aspects of grammar.
LyricsTraining can help you practice listening too.
Toucan chrome extension can help with vocab.
Le Monde/ news websites can help with reading.
Italki/ HelloTalk/ Tandem are good for practicing spontaneous language use, each of them is slightly different in terms of what is free/paid for/ how much things are, so it might be worth having a look at all 3 and deciding if any of them are helpful.
TV5Monde for French TV
Youtube channels: Les Astuces de Margaux, Hugo Decrypt, Montreux Comedy
To add on, for essay writing (best for A-level / university), the book Mot à Mot is good. For reading, I found it useful for my very first French book to read a side-by-side translated one - so it had the French on the left side of the page and the English on the right. I chose The Le Petit Prince, but you can also get The Portrait of Dorian Gray and A Christmas Carol on Amazon.
I'd also say similar things to everyone else's suggestions.