Due to using the vanilla legendary slot as an entry point for its mechanics and functionality ECO is able to modify all kind of equipment without requiring patches for other mods or Creation Club content. Therefore you should avoid using similar legendary crafting/swapping mods but since ECO includes all of their features there should be no reason to combine them with ECO. Mods with custom legendary effects that don't add ECO's dynamic slot system can be made compatible by following this guide. All other mods are compatible right out of the box.

For expansions and patches you might be interested in, go to ECO's description page, click on the Requirements tab and under the "Mods requiring this file" section you'll find them. Some of them are also listed below.

If a mod you're using isn't listed below I'm either not aware of it, never used/tested it or they are so different that they'd never could conflict with ECO. If you're unsure about conflicts in your load order use FO4Edit's "Filter for Conflicts" feature.

Recommended Mods:

• Mod Configuration Menu (MCM): This one allows for easy configuration of all of ECO's settings without the need to carry the holotape around with you the whole time. And it's way faster and clearer than the holotape config.
• Configurable Hotkeys: Configure several hotkeys via MCM that allow you to create standard saves, use items, wait anywhere, execute console commands or custom functions.
• FallUI - HUD/Inventory/Workbench: This makes advanced UI and HUD features available and can be considered an improved/advanced version of DEF_UI. Definitely check those out if you want to use an item sorter mod but their features are useful even without a sorter. Scroll down on the linked mod pages to see all the other modules of this awesome suite or visit the author's user page for even more high-quality mods.
• FallUI Item Sorter / Complex Item Sorter: If you want to use an item sorter I strongly advise against using those that bake their tags directly in static plugins (like VIS, VIS-G, etc.) because they unnecessarily cause a lot of conflicts with other mods and cause them to break depending on their spot in your load order. Both FIS/CIS on the other hand are highly compatible with other mods. With them you'll no longer need to create or download patches for your item sorter. CIS even has full ECO support and modular patching options for ECO's functions integrated.
• Global Stash or Junk Scrapper: For your storage and junk scrapping needs. It automatically connects to ECO's workbenches (even the mobile ones) and also allows you to scrap junk automatically.
• No AWKCR and AE For Mods File Dump: Remove the AWKCR dependency from your mods and make your load order more stable.
• Weapon Integration Project (WIP): Overhauls many popular weapon mods, fixes bugs and inconsistencies and also expands them with full integration into ECO's custom systems for a seamless experience.
• Free Crafting Patcher: If you don't like the fact that everything in ECO costs precious materials and requires perks then you can change that easily.
  

• All mods that don't override vanilla legendary effects and associated forms.
• AWKCR: Technically ECO is compatible with that mod. There are a couple minor conflicts (not really worth the time creating a patch for). But since AWKCR has way too much impact on game performance and stability for my liking I won't provide compatibility patches or support it in any other way. ECO is meant to be a lightweight alternative to AWKCR and the mods that rely on it.
• Better Mod Descriptions / Even Better Mod Descriptions: Load ECO after them because ECO's descriptions are more up-to-date and detailed.
• More Power Armour Mods (More Power Armor Mods): If you use ECO and MPAM simultaneously you'll have three Misc slots available but there aren't any conflicts.
• Power Armor Materials AND Paints (PAMAP): If you use ECO and PAMAP simultaneously you'll have three Material slots available but there aren't any conflicts.
• Standalone Workbenches: If you want to use those benches instead of or in addition to the Universal Workbench and have all of ECO's recipes available on them (including transferred ones from the Workbench Patcher) then use the resp. patch part of ECO's installer.
• VAFS / VAFS Redux: Load ECO after VAFS (Redux). You might not see some altered descriptions from VAFS but both mods will work properly. If you care for that aesthetic change then you can use the patch part of ECO's installer.
  

• Armorsmith Extended: Most of AE's features are already included in ECO in a more lightweight and compatible fashion. But you could run ECO + AWKCR + AE, even though I consider it a cursed combination. If you still want to run it make sure to have ECO's plugin sit below AE's plugin in your load order or you might find some things not working as intended.
• Unified Clothing Overhaul (UCO): Check AE's paragraph above. Besides that, UCO alters vanilla legendary effects which usually isn't a big deal because you could simply have ECO sit below UCO in your load order and resolve that conflict that way. The problematic part is UCO's crafting recipes for those legendary effects because you might find them replacing ECO's own ones. And when scrapping legendaries not getting Legendary Microchips in return. So, in almost all cases you want to disable UCO's legendary recipes with FO4Edit.
• Legendary Modifier Rebalance: This mod would require a rework so that LMR's changes to legendary effects (behind the scenes) match ECO's detailed descriptions for the legendary effects. Both mods might (partially) work without a patch if you load ECO after LMR but then you have to keep in mind that the descriptions might no longer match the actual effect.
• Transfer Settlements: The following probably applies to the same function within Workshop Framework as well. The scripts that control the export of your settlement setup cause problems when it comes to exporting objects that spawn additional objects, like in case of ECO's Universal Workbench (UW). They export the UW (activator) and also the invisible workbench modes individually. So, when you import that layout that had an UW placed it'll place the UW and the exported set of modes and then the UW spawns its own set of modes via script. You'll end up with two sets of modes stacked in the same spot. That on its own isn't problematic until you scrap or move the UW, it'll leave the individually exported set of modes behind while those can only be removed by console commands. To circumvent that either remove the UW before exporting or clean the exported layout file from the invisible workbench modes.
  

• Mods that make changes to vanilla legendary effects or their associated forms. That includes mods like Legendary Modification, VIS-G Legendary Modification, Love to Craft - Legendary and other similar ones.
• The Legendary Overhaul (TLO): This mod is a performance hog, a nightmare to deal with in terms of compatibility and doesn't properly work with ECO's legendary system anyway.