If you're familiar with installing mods then check out the below, if you've not installed mods or custom content (CC) before then check out my how to guide and then come back to this post.
Camera Mod
Lowedeus's Camera Compilation - A compilation of camera mods that improve the standard game camera both in map view and lot view. This is particularly useful if you are using the custom skylines/skies detailed below. !!!Remember to install these in the camera folder not the downloads folder!!!
Lighting Mod
Cinema Secrets - improves vanilla game lighting.
My reshade pre-set - this is my personal reshade pre-set I adapted from my Sims 4 one, it brightens, sharpens and increases saturation of colours (nothing too fancy!). !!!Remember to install reshade before downloading and follow the instructions of how to install a pre-set!!!
UI Mods
Clean UI mod - overhauled and modernised UI (some mods listed below are included so check this on the mod description page, also make sure you pay attention to the order the mods need to load in as in the description).
No red border when paused - this mod removes the red border around the screen when the game is paused.
Improved family tree UIÂ - this mod increases the size of the family tree UI to make it easier to see with modern screen resolutions.
Organised sim pie menu - this mod organises and simplifies the pie menu when you click on a Sim.
Improved pet UI - distributes the buttons on the pets UI pets better.
Improved hobbies UI - improves the look and size of the hobbies panel
Smaller plumbob - makes the plumbob over the Sim's head in live mod smaller.
Replacement plumbob for groups outings - replaces the blue group outing plumbob with a new icon.
Cleaner skill bar and purchase bar - changes the look of the skill progression bar and the purchasing bar for customers to make them cleaner.
Photo screen overhaul - changes the look when taking photo to make it cleaner.
Aesthetic Mods
There are many mods out there to improve the look of your game, here are just a few key ones:
Default replacement trees - this mod replaces the trees in the neighbourhood with prettier ones.
Default replacement roads - this mod replaces the roads in the neighbourhood with better, but still maxis match ones.
Default Replacement terrain- this mod replaces the terrain with better, but still maxis match ones.
Custom sky (map and lot view) - allows you to place custom skies in the game for prettier and more dynamic skies/clouds in map view and in lot view.
Custom skylines -install a custom skyline around the world viewable on both map view and lot view.
Sun/Moon Replacement - default replacement to improve the look of the sun and moon.
Lot lighting fixes - fixes a lot of lighting issues.
Soft outdoor shadows - softens outdoor shadows to make them less blobby.
Pond and Sea Water Overhaul - drastically improves the look of pond and seawater (remember you need a pool tile on the lot for it to work).
Replacement snow - replaces the snow in the map view to look better.
Replacement snowflakes - default replacement for snowflakes with prettier ones
Replacement hearts - default replacement for the love/chemistry hearts with prettier ones
Replacement thought bubbles - replaces the thought bubbles with better looking ones.
Replacement book covers and icons - replaces the icons used when a Sim writes a novel and the book cover.
Remove "family" from loading screen - remove's the word "family" from the loading screen when you load a household.
Replacement roses - replaces the roses you get as a date reward.
Replacement champagne - changes the look of the champagne.
Replacement engagement box and engagement rings -replaces the proposal box and rings.
Replacement mobile phone - replaces the mobile phone to look more modern.
Replacement love tub - replaces the love tub reward object with a new one.
Replacement bath water - improves the look of the bath water.
Replacement bath bubbles - improves the look of the bath bubbles.
Garden plants gussy up - replaces the look of the garden harvestables.
Replacement trash can - replaces the trash can on community lots.
Create-A-Family
Widescreen CAS camera - this mod makes CAS fit better on modern widescreens.
Wider CAS Columns - moves the columns in CAS further to the right, fitting modern widescreens.
Clean CAS background - replaces the CAS background to a much cleaner one.
No Smiling in CAS - stops sims smiling in CAS so it's easier to apply alter their appearance and apply make-up etc.
Default skin - replaces Sim's skin, more natural colour, gives wrinkles to elders and includes occults.
Default eyebrows - default replaces Sim's eyebrowsÂ
Default lips and eyeliner - replaces Sim's lips and eyeliner
Face templates - adds extra face templates to the gameÂ
Bodyshop sliders added to CAS - Adds the extra sliders found in the Sims 2 Bodyshop programme to the main game Â
Broken face template repairs - there are some broken face templates in the original game that have been fixed with this mod
Overly bright CAS fix - sometimes CAS can be too bright, this mod fixes
Unlocked Uni outfits - unlocks the clothing that was previously only for college students
Misc
Less dog barking - reduces the amount of dog barking in the background of the game.