If you happen to live in Sweden, i would recommend Avanza Zero[0]. Swedish index fund with no fees at all, not even courtage. (I do not work for Avanza or have any affiliation)
Swede & Avanza customer checking in. Can definitely recommend them. If you reside and Sweden, make sure to open a ISK, not an Aktie- och Fondkonto (stock & fund account).
Living in Germany and have not been able to find a bank with the same kind of service and reliability. Comdirect comes close, but not good enough for me to close my account with Avanza.
[0] https://www.avanza.se/vart-utbud/handel/avanza-zero.html