The best links to external websites are listed here. No affiliate links are used - This is not about fiat money, this is about freedom.
Blocktrainer
Website with a lot of valuable information and tutorials about Bitcoin and related products and services [German/English].
Mempool
Website which displays the mempool (queue of pending and unconfirmed transactions) and a block explorer (viewer for real-time and historical information about the Bitcoin blockchain) [Multilingual].
Timechain Calendar
Dashboard wit a lot of information like the actual blocktime, Bitcoin price in USD, mining difficulty, subvention/block, transaction cost [Multilingual].
Bitbo Dashboard
Bitcoin dashboard with many different stats about nearly everything related to Bitcoin [English].
Bitcoin Treasuries
Website which lists Companies, Funds, Governments with Bitcoin on their balance sheet. [English].
BitBox
BitBox02 is a very good hardware wallet which I personally use. This wallet is best for storing medium and large amounts of Bitcoin.
Pocket Bitcoin
With Pocket Bitcoin you can easily buy Bitcoin in Switzerland and later send it to your hardware wallet. A service I often use.
Swan Bitcoin
Swan is a US based company where you also can buy Bitcoin, hold it there or better send it to your hardware wallet.
BitBar
The BitBar is a steel backup to store your seed phrases against flood, fire and other bad circumstances.
Aqua Wallet
Aqua Wallet is a great phone wallet to store smaller amounts of Bitcoin or Tether. You can use the wallet to pay over Bitcoin (main layer), Lightning (second layer) or Tether in an easy and convenient way.
Tangem Wallet
The Tangem wallet is a new hardware wallet in credit card form. It is not easy to detect at airports/customs but should only be used for small and medium amounts of Bitcoin.