Most notable products from tech companies were originally acquisitions. Free cash flow means fast-growing startups can acquire to expand or acquire to turn a flywheel. For companies like Google, any company that provided more data or more searches was a prime target for acquisition. Here's a list of some some everyday products that we know and associate with large tech companies that started somewhere else.

Acquiree Acquirer Price Year
PowerPoint Microsoft $14M 1987
Photoshop Adobe $35M 1995
Chipsoft (TurboTax) Intuit $225M 1993
86-DOS Microsoft $50,000 1981
Android Google $50M 2005
Pixar Steve Jobs $10M 1986
YouTube Google $1.65B 2006
Instagram Facebook $1B 2012
eBay PayPal $1.5B 2002
Applied Semantics (Google AdSense) Google $102M 2003
NeXT (Steve Jobs) Apple $400M 1996
VMWare EMC $635M 2003
Booking.com Priceline $135M 2005
DoubleClick Google $3.1B 2007
Where2 (Google Maps) Google <$50M 2004
WhatsApp Facebook $19B 2014
Venmo Braintree $26M 2012

Some honorable mentions:

"Too early to tell" where they rank, but some more recent acquisitions.

Not true acquisitions, but investments that owned a substantial part of a growing business.