Ten apps that survive in founder stacks across multiple ventures. Each one solves a recurring problem rather than riding a hype cycle.

1. Slack — team async chat
2. Notion — wiki, tasks, docs in one surface
3. Google Workspace — docs + calendar + sheets
4. Cal.com / Calendly — scheduling links
5. Stripe — payments
6. HubSpot — CRM with free tier
7. Zapier — workflow automation between tools
8. Loom — video explanations replace long emails
9. 1Password — team credential sharing
10. ChatGPT / Claude — the 2026 default for drafting, summarising, analysis

Ten apps. Add from the broader universe as specific frictions emerge — not proactively. Every added app is a new surface to maintain.