TL;DR: All single-player downloadable content for Dragon Age: Origins, Dragon Age 2, Mass Effect 2, and Mass Effect 3 is now free. The good news comes as a result of EA decommissioning the unpopular BioWare Points system, which used to be the only way to buy these add-ons.
EA will remove BioWare Points from its Origin game store on October 11, according to an email the company recently sent out to users. Before 2017, the currency was the only way to buy DLCs for older Bioware titles including Dragon Age: Origins, Dragon Age 2, Mass Effect 2, and Mass Effect 3.
As a result, all single-player add-ons for these games are now available free of charge. You'll have to go to your game library, select one of the mentioned titles, navigate to the "Extra Content" pane, and get each DLC separately (Mass Effect 2 alone has over a dozen of them).
It's worth noting that Mass Effect 3's multiplayer packs aren't free. EA mentions you'll be able to purchase these until October 11 using any leftover BioWare Points you might have. After that date, they'll only be redeemable using Credits you've earned (read: grinded) in-game.
Interestingly, EA is still selling DLC bundles for these games separately. The company introduced these bundles in 2017 due to user complaints about BioWare Points never going on sale, meaning that buying all DLCs for a game was often more expensive than the game itself. They also only came in packs of at least 400, while some add-ons went for as little as 160 points.
In the email, EA also emphasizes that you'll still have access to any content previously purchased using BioWare Points, perhaps referencing recent news that gamers will lose access to paid DLCs for some Ubisoft games.