These are all products that I happily use. If you also become a customer by using one of my links or vouchers below I get a reward. Thank you!

Finance:

Banking (Income & Expenses) -> ING Girokonto (Free as salary account or age below 28; optional girocard 0.99EUR/M; 50EUR for new customers, 20EUR for me)
Banking (Saving) -> ING Extrakonto (Tagesgeldkonto; Free x3; 50EUR for new customers, 20EUR for me)
Banking (Investing in Stock Index Fonds/ETFs) -> ING Direkt-Depot (Free; 50EUR for new customers, 20EUR for me)
Banking (Travel; Free; All currencies without exchange fees) -> Revolut (2023 May 80EUR for me)
Banking (Business & Personal Giro) -> N26 Personal/Business (Free & 100% digital; 30EUR for me)

Technology:

Webhosting (including domains) -> Netcup -> Contact me for product specific vouchers (usually 30% discount)
netcup.de