Running the Curse of Strahd D&D campaign? I highly recommend these additions

Beadle & Grimm's props | View at Amazon
Although I like to use miniatures wherever possible, I tend to prioritize props these days. They can make a tremendous difference to the atmosphere at the table, bringing the story from your imagination and into real life. I personally like to print off and paint models using my 3D printer and free files from Thingiverse, but that's a lot of work and outlay – an easier solution is to grab the official tie-in props from Beadle & Grimms. This pack includes the Holy Symbol of Ravenkind (an essential in-game artefact players must find), a puppet of Strahd himself that the party finds in a toy shop, and Barovian coins that you can use as inspiration markers.

MandyMod additions | View at Reddit
If you'd like to run a Strahd campaign that's as close to the original as possible (while still enhancing the overall experience), MandyMod's notes will be exceptionally helpful. This was the first addition I made to my own sessions, because their advice on how to run each area – including the campaign's vestiges with their Dark Gifts – is both insightful and deviously clever. I wouldn't dream of running Strahd without it now.

Wizkids Curse of Strahd miniatures | View at Amazon
Looking to spice up battles? Grab some miniatures so that your players can see exactly what they're facing, and where. Wizkids makes official Curse of Strahd models, and they're widely available at Amazon. Alternatively, and if you have access to a 3D printer, I'd recommend the Loot Studios "Scarlet Requiem" pack. It has some truly excellent alt-Strahd models.

Syrinscape | View at Syrinscape
One of the best discoveries I made while prepping for Curse of Strahd is this audio service. It has official soundtracks, sound effects, music, and more for the campaign, and it's used like a DJ deck with button-activated fade ins, outs, or surprise drops. You can grab a membership to access all of the site's contents, or purchase the Curse of Strahd pack itself. Either way, all this can be shared online with your players to listen along with – but you're still controlling it all, so they hear exactly what you want them to hear.

Tarokka Deck | View PDF at D&D Store
Much like the Beadle & Grimm's accessories linked above, having a physical Tarokka Deck for the iconic fortune reading does a lot to draw your party into the world of Barovia. It's also handy for the party to have something they can physically reference later in the campaign, too – while that reading may have occurred a few days beforehand for the characters, it probably took place weeks ago in real-time. While it's tricky to find the current, physical version of these right now (you may have to make do with the PDF linked above), don't worry – a new physical edition is due to launch alongside Ravenloft: The Horrors Within in June. If you want something before then, you can always check out custom, fan-made cards at the likes of Etsy.

DragnaCarta rewrite | View at Curse of Strahd: Reloaded
For those who want to supercharge their campaign with extra quests, backstory, lore drawn from previous editions, and better-balanced fights, DragnaCarta's work is a must. The level of work that's gone into this is staggering; it's a top-to-bottom rework that keeps the core of Strahd, but enriches areas that were lacking depth while also adding to characterizations across the board. My campaigns use a mix of DragnaCarta's work, MandyMod's suggestions, and my own notes, and I'd highly recommend doing the same – picking and choosing what to use allows you to create a magnificent patchwork that suits your party's needs.

DM Andy maps | View at Patreon
The battlemaps provided in the original campaign are fine, but they've got nothing on DM Andy's stellar work. These revel in the gothic darkness of Barovia, and they're available for a very reasonable price. Just sign up to a month's subscription to access the entire collection, and cancel whenever you want once you've downloaded what you need.