Software

https://www.hmailserver.com/functionality open source email server
http://www.getusb.info/flip-your-bit-usb-utility-to-make-local-drive/ make bootable usb drive
http://getgreenshot.org a powerfull and simple printscreen tool (i prefer this one)
http://www.gadwin.com/ another free printscreen tool (used it for a long time until i found greenshot)
https://getsharex.com/ Open Source and most complete... (i prefer this one as it is open source, packed with features and till small and efficient.)

some tools like jabber, mumble teamspeak etc.
https://www.gamevox.com/en/
http://www.jabber.org/ 
http://www.mumble.com/
http://www.teamspeak.com/
http://www.ventrilo.com/
http://discord.com
https://notepad-plus-plus.org/download/v6.9.2.html

https://www.safaribooksonline.com/library/view/professional-microsoft-iis/9781118417379/c04_level1_4.xhtml

http://www.compucated.be/fun/255-alt-codes-voor-jouw-toetsenbord/   (alt-codes to use with numeric keypad)

Obfuscate mail or phone number to protect against harvesting tech. (not 100%, but blocks most)
http://www.albionresearch.com/misc/obfuscator.php

important tools for everyone who needs to investigate a windows server (or workstation)
https://technet.microsoft.com/en-us/sysinternals/bb842062.aspx

https://www.whatsmydns.net/#NS/it-pro.nl

http://www.eventid.net/ investigate your windows eventlog codes

http://www.satsignal.eu/ntp/setup.html software to windows NTP time setup (with information)

Log analyzing tool: https://www.loggly.com/
Infra / Application Monitoring www.newrelic.com and www.datadog.com
PRTG www.paessler.com
NAGIOS www.nagios.com

Puppet www.puppet.com
Chef https://www.chef.io/#/ 
Ansible https://www.ansible.com/

(windows) Runbook Automation https://technet.microsoft.com/en-us/library/dn469260(v=sc.12).aspx (Orchestrator)

Oracle Virtual Box https://www.virtualbox.org/ 
Virtual networking https://www.gns3.com/

Collaboration tools

collaboration tools

https://www.wrike.com <-- i dunno
https://basecamp.com/ <-- not tested
https://trello.com/ <-- nice but simple
https://dapulse.com <-- $$$
https://yougile.com <-- nice tool
https://www.lucidchart.com online powerfull alternative for Visio (limited free version)
https://www.office.com/ office 365

Firmware

firmware zyxel modem VMG8324-B10A"
http://www.zyxel.com/euosearch/dl-search.aspx?mci_country=be&mci_lang=nl&keyword=VMG8324-B10A&submit=Search

Remote Desktop Software

https://www.royalapplications.com/ts/win/features Royal TS (free version available)
https://remotedesktopmanager.com/ Devolutions RDP suite (free version available)
https://www.microsoft.com/en-us/download/details.aspx?id=44989 remote desktop connection manager 2.7 (free version)

Loggly https://loggly.com
LogStash
https://www.elastic.co/products/logstash