The last two years, SDS has included a very high-end card for an extensive collection (it was Honus Wagner in 2019 and a flashback Trout in 2020). These required you to collect a high volume of cards from all the different collection tabs. That collection was in like the July/August timeframe.
This included all the different legend/flashback categories (All Star, Monthly, Veteran, etc.) and some of the larger collection rewards (so like the Chipper this year or the 99 OVR Jackie from the 42 collection).
If you're a collector, it behooves you to hold onto cards so you have a step up. Last year; some collections needed for the Trout were REALLY hard to get. For example, Postseason cards were hard to get...folks that had sold some free bronze cards were having to buy them off the market and prices shot up (some were going for 100k+ stubs) as people were trying to complete the collection.
One general piece of advice. I strongly suspect that the gold prospect cards will be a collection element this year. You can earn these 'free' by playing through the US Conquest map (but, to earn them all, you'd need to play through it 5 times). Yes, you can buy them off the market...but even now, they are running about 5k each in the market...if they are part of the collection, they WILL shoot up in price big time. Get ahead of the curve, collect them and be ready.