On-Screen Ruler - lightweight, free, semi-transparent ruler

Everleagues - Everleagues is a cloud-based application that offers team communication, file sharing and storage, data tracking, and activities management.

Meazure - What are the dimensions of that image? How big is this window?

openmeet - Account free video conferencing with a rooms component that lets you use VC within a physical meeting room. The server can also be hosted in your own cloud for extra privacy/security.

Bluegrams Screen Ruler - A lightweight and configurable ruler tool for Windows Desktop.

Stork.ai - AI-Based Collaboration for Hybrid Teams. Rich media messaging, advanced video and voice conferencing, auto-transcribing and screen sharing. Serendipitous meetings at the water-cooler with your human and AI teammates.