qBittorrent

You want a clean, powerful torrent client with no ads. qBittorrent is the top pick: an open-source, ad-free BitTorrent client, with built-in torrent search, sequential downloading, rate limiting, RSS feeds, and a Web UI for remote management, a popular open-source, ad-free alternative to µTorrent. Cross-platform, open source.

Features

BitTorrent: Open-source, ad-free torrent downloads.

Built-in search: Built-in torrent search.

Remote Web UI: Manage remotely via Web UI.

Open and free: Cross-platform, open source, free.