Almanac is described as 'knowledge base that combines wisdom from tech leaders with your team's own practices' and is an app in the Office & Productivity category. There are more than 100 alternatives to Almanac for a variety of platforms, including Online / Web-based, Windows, Mac, iPhone and SaaS. The best alternative is Joplin. It's not free, so if you're looking for a free alternative, you could try Notion or Microsoft OneNote. Other great apps like Almanac are Trello (Freemium), Evernote (Freemium), Simplenote (Free, Open Source) and Google Docs (Free).
Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, can be copied, tagged and modified either from the applications directly or from your own text editor.
With so many tools, it's hard to keep everyone on the same page. Notion is a new tool that unifies them all. It's like Google Docs, but everything is organized and discoverable by your team. Real collaboration in real-time.