Apple - Source for all things Apple
MacUpdate -The latest applications and updates without malware
Microsoft -Source for Microsoft products like Office and SilverLight
Adobe - Source for Adobe products and updates
Other World Computing - Source for Mac specific upgrades power supply replacements, batteries, and peripherals
Mission Repair - Repair of computers not covered by Apple warranty
MacTracker - Database of all Apple products manufactured, includes newest OS you can run, maximum memory, and available drive space from the factory.
Data Memory Systems - Supplier of memory, replacement drives, USB/CSD flash drives/cards
iFixit - Source for parts and repair guide
Current versions of applications:
Firefox - 59.0.2 - New speedier version. Try it.
Office 2011 - 14.7.7 (available through Microsoft updates with the application)
Office 2016 - 16.19 (available through Microsoft updates with the application)
Adobe Reader DC - 2018.011.20035
Adobe Flash Player - 126.96.36.199
Adobe Shockwave - 188.8.131.52
Java - Version 8 Update 161 Build 12
Silverlight - 5.1.50901.0 (No longer supported for Google Chrome)
Available through your updates at the App Store: iTunes 12.X, Apple OS Sierra (11.0.2), Apple Updates for 10.10.x, 10.11.x,10.12.x and 10.13.x, Apple Safari 9.11, 10.0.13, and 11.0.1, and for your iOS device 11.2.6.