If you only want for taunting you can try the attached plugin. I believe the original author was noyb? I just updated it with current effects and made it work with version 1.11 of SourceMod. It's very similar to the Unusual Taunts plugin by SrikeR14 but doesn't require SteamTools or a Steam API Key.
When you use the command of !utaunt a menu will appear allowing you to select the unusual effect you want. Sadly there are 26 taunt effects that don't work well with this method. In those instances I commented out the effects so they don't appear in the menu.
These unusual effects will only appear when you taunt since that is what you asked for. If you want unusual hat effects or unusual taunt effects while not taunting you'll need a different plugin.