Microsoft Visio has a big user community, you can find stencils on many platforms including reddit. If you don't find something, try third party commercial shape vendors such as 3DN, NetZoom, Shape Source, or Visimation.
I try to keep my artefacts as fresh as possible by manually downloading them on a regular basis, sadly most vendors does not update them frequently. Furthermore, many stencils are only available to current customers via their support portal.
The repository also include more than 1,200 IT stencils older than 2019 because I have them and organizations are still using them.
- AXIS Communications
- BB SmartWorx
- CAELFFI Hydronic Solutions
- Corning Optical Communications
- EVTrack Access Control
- FMC Modeling
- Legrand Data Center Solutions
- Leviton
- Opto22
- Premium-Line
- Rittal
- Taco
- Tekmar Design
- Unipower
- Westernmo: industrial Ethernet switches and data communications products
- Omnitron Systems
- ECCEMAN: 2D symbols for computer network diagrams
- MTMnet.com's Visio Icon & Stencil Library
- Visio Shapes for Card Access, Intrusion and CCTV: created by Duncan Miller and based off of the Security Industry Associaion Standard CAD Symbols
- A10 Networks
- Adtran
- Alibaba Cloud
- Allies Telesis
- APC
- Arista
- Avaya
- AWS
- bitbucket
- BlackBox
- CABLExpress
- CheckPoint and complimentary netZoom stencils
- Ciena
- CISCO products, Meraki and Conceptual Icons
- CommScope
- CyberPower
- Eaton
- EdgeWave
- Emcor Enclosures
- Extreme Networks
- F5
- FIM-MIM stencils
- FireEye
- Fortinet
- Garland Technology
- GigaMon
- Google Cloud and a github repository
- Hanwha Techwin America
- HellermannTyton
- Huawei
- IBM
- Imperva
- Infoblox
- Juniper
- Kemp Technologies LoadMaster
- Kubernetes
- Lantronix, formerly UP Logix
- Meinberg Global
- Microsoft
- NVIDIA
- One Identity
- OpenGear
- Oracle
- Palo Alto Network
- Panduit
- Poly, formerly Polycom
- QNAP
- Raritan
- Riverbed
- Splunk
- SuperMicro
- Synology and Sean Paul Evans
- TP-Link and here
- Tripp Lite
- TrueNAS
- Ubiquiti and dropbox
- Veeam &Rhys Hammond
- Vericom
- VIAVI Solutions
- VMware Validated Design and Design Decisions
- VMWare and a github repository
- VTR Systems and a github repository
- WatchGuard
- WTI
- Zscaler
- Digi
- ADAPT (Application Design for Analytical Processing Technologies)
- BPMN, CMMN, and DMN
- Business Intelligence – Data Vault Guru Based on a book by Patrick Cuba
- C4
- CORAS Model-driven Risk Analysis
- Enterprise Integration Patterns and/or Enterprise Integration Patterns
- IDEF3
- IDEF5 Based on on the IDEF Methodology
- LACATRE – Langage d'aide à la conception de systèmes temps réel
- Open Smart Grid IATF 3.1
- ORM Foundation
- Subject Oriented Business Process Management also known as Abstract PASS (Parallel Activity Specification Schema)
- SYSML
- UML 2.5