First of all there are thousands of addons in the workshop and it's impossible to make L4L compatible with any of them.
That being said, L4L should be compatible with most addons. There should be no issues with purely cosmetic addons and it should be compatible with most vscript addons. However, there might be some vscript addons that can cause issues.

One known issue is the vscript hooks overwriting problem which leads to the addons that use L4L (like Left 4 Bots, Left 4 Fun, Left 4 Grief) no longer responding to commands (can be chat, console or vocalizer commands or all of them).

There is a chance that you can solve this issue by forcing the game to load the other addon before Left 4 Lib.
If you are having this issue you can try this:

1. Find the addon that is causing the problem. This is the boring part, you need to disable the other addons and enable one by one until you find it. You can skip the cosmetic addons. Unfortunately there is no other way to do it.

2. Go into the list of addons and disable it (don't unsubscribe).

3. Close the game, open the game folder and navigate to "addons\workshop" subfolder.

4. Locate the correct .vpk file, copy it (CTRL+C).

5. Go to the parent folder "addons", now paste the file (CTRL+V).

6. Open the game, go to the list of addons. Now you should see 2 copies of the same addon, one disabled and one enabled. Make sure that the one with "View on workshop" button is disabled and the one without is enabled.

7. Play and see if it worked.

Usually this should be enough as the local addons are loaded before the workshop ones.
In case you have both addons local (in "addons" folder) you can try to change the loading order by editing the "adonlist.txt" file in the game's main folder and move the entry with the other addon on top of the list and save the file.

If, after all of this, you are still having the issue, then consider the addon incompatible as there is nothing else you can do.

NOTE:
Before you start, make sure that your issue really the "hooks" issue and not another one.
For example: the chat and console commands are working, only the vocalizer ones are not. Are you sure you didn't accidentally set the "vocalizer_commands" L4B setting to 0 and your "vocalizer.txt" file is ok?
Also, if you set "users_admin_notice" to 1 in the L4L "settings.txt" you should see the green "Admin yourname joined" on screen when you start a game. If you don't see it is possible that the commands aren't working simply because L4L is not recognizing you as admin, so it's a different issue (maybe try deleting the "admins.txt" file).

If you find addons that remain incompatible no matter what you try, you can post them here so the other people can find them quickly.