In the past I have used a Neo Freerunner (with Om2007.2 and later SHR) and then a Nokia N900 (with Maemo 5). The former demanded plenty of your attention but could be made to work well enough, while the latter was a really nice yet exceptionally hackable consumer device. Before I switched to a Librem 5 I had carried a second phone with Android for about 3 years as the N900 was already too old for comfortable web browsing and there was nothing else on the market that I'd consider worth switching to for a while - but that was the only such exception.