Apps similar to mempool include OrangeDeck, which is free and open source. Other options are OpenBitcoin. Between them they cover Windows, Linux, the web and Android.
Bitcoin mempool visualizer for Linux, Windows and Android, with a block height clock, a Bitaxe monitor, a block explorer and market data.
Bitcoin-only block explorer serving all data directly from its own Bitcoin Core node and address index, featuring detailed address histories, live rich list, balance chart, mempool and fee stats, halving countdown, node census, and fully open-source backend.
