This list is filtered from a Reddit thread.
QuoteWerks: project proposal & quoting management system. Looks hardcore, probably geared toward complex products involving managed services, service/product integration, value-added reselling, subcontractors, manufacturing, software solutions, etc.
TeamViewer: remote desktop software. Remote PC access.
Dialpad/Uberconference: office telephony service/teleconferencing service.
Pushbullet: helps sync up notifications and other information across devices.
Screenflow: affordable video editing and screen recording software for Mac.
Swydo: reporting, monitoring, and workflow for online marketers.
Visual Studio Dev Essentials: free software tools, cloud services, and training.
Grasshopper: business telephony. Get a main business phone number and set up extensions for multiple endpoints.
Agile CRM: customer relationship management.
EmailOctopus: email marketing campaign management like MailChimp or Constant Contact, but way less expensive.
AutoHotkey: automation scripting language for Windows.
Airtable: database system with a web-based GUI that combines features of spreadsheets and databases.
Gusto: HR services.
InvoiceNinja: freemium and open source invoicing system.
Deputy: workforce schedule management.
TextExpander: insert prewritten snippets of text as you type.