LGBTQ items. Found this in a speculation & rumor thread. It's all the stuff that should be coming in patch according to original poster (forgot to copy their name ?). List is pretty long..
Patch content I am aware of (from GC live stream), coming with June 18 patch.
Fishing Overhaul (similar to the gardening overhaul that came pre-Seasons):
New fishing spots in various worlds
Re-tuning of fishing skill (could be new unlocks, bait/weight/rarity/location changes for fish, update to notebook feature on phone etc)
New high level cast animation (this might be exclusive to IL though, it wasn't clear)
Some extra fishing types also come exclusively with IL (Spear-fishing, setting fish traps and fishing from boats)
Part Time Job Overhaul:
Part Time Jobs available for all sims teen and older.
Some jobs have a choice of shifts to choose from.
You can hold down two part time jobs simultaneously if you choose shifts that don't overlap.
Lot Traits:
Off-the-Grid (no utilities, limited internet but no bills) - Catalogue entries for interactive/motive objects will indicate if they can be used off-grid.
Clothing Optional (nudist/naturist lot) - Most sims will choose to be nude while on this lot except for those with certain traits (Childish, Squeamish, Prudish? (might mean Unflirty).
Build/Buy:
Portable plastic lounge chair - Various BG matchy swatches (please note that while you can sit, relax, drink and nap on these loungers, you cannot sunbathe without IL)
Stilted foundations - (Be warned - you cannot decorate under these because of how floor levels work in TS4, deco always pops up unto the foundation level. Might be able to find workarounds with a basement level and MOO but that won't work on the new water lots)
Ceiling fans updated to turn on/off and cool rooms (with Seasons installed)
350 BG door swatches - While the date of this hasn't actually been confirmed it has to release by the end of the quarter (June 30) due to free-content announcement/release laws.
Pride month content - I wall flag, possibly other content.
CAS:
Recolours of the BG toddler diaper - I guess for it to be used as swim diapers with the new EP Trait randomiser button (finally!) - Also in gameplay when aging up. Does not randomise the aspiration. Pet trait randomiser if you also have C&D.
There will likely also be some under-the-hood changes for the EP and bug fixes/new bugs as usual.