Sequoia Capital. Arguably the most influential venture firm in history — early investors in Apple, Google, Oracle, Cisco, Airbnb, Stripe, WhatsApp, and ByteDance. Known for its disciplined partnership model, long-term founder relationships, and willingness to concentrate capital behind conviction bets. The firm's memos and market-reset notes (like "RIP Good Times" in 2008) still shape how founders and investors think about downturns.