Welcome to the community! 
There are many videos online for stuff like this, including websites dedicated to alternatives, like https://alternativeto.net.
Are there any specific software that you have in mind?
Also, Spectacle is specific to KDE Plasma (the desktop environment you see when you log into your system).
→ A more universal screenshot utility I use is Flameshot, which works in most, if not all, Linux environments.
PS: You can also check out this thread for some apps that people on this forum are liking:
And for many of the apps that you used on Windows, they may already be available on Linux/Arch. You can check here: https://wiki.archlinux.org/title/List_of_applications