I'm a long time user of IRC and bitlbee (I wrote my own IRC bridge for a popular webchat back in 2004) and the last few years I've been using weechat-android as

I'm a long time user of IRC and bitlbee (I wrote my own IRC bridge for a popular webchat back in 2004) and the last few years I've been using weechat-android as a mobile client and it's not too bad. It's still IRC, so image/video/gif attachments are out of the question, but for someone who's been using text-mode IRC clients for the last 20 years it's a godsend.