Stadia Pro is the paid service of Stadia, which includes games you can claim as part of the subscription and after claiming play as long as you are subscribed. That is in difference to Stadia Basic, which is free but doesn't offer free games as part of the subscription. In both Basic and Pro you can pay for games in the full catalogue to play them unlimited (even without subscription).

In October six new games are claimable for Stadia Pro members:

• Dead by Daylight → this game features Crowd Coice (see below)
• Human: Fall Flat
• Superhot: Mind Control Delete
• Lara Croft: Temple of Osiris
• Celeste
• Jotun

Three games will only be claimable as part of Pro by September 30th, so claim them now! These will still be available for purchase later on, but this is the last chance to get them free as part of the subscription. The three games are:

• Monster Boy and the Cursed Kingdom
• The Turing Test
• Metro 2033 Redux

Other 23 games that are currently included in Pro stay available for claiming in October:

• Super Bomber R Online
• Hello Neighbor
• Hitman - The Complete First Season
• Gunsport
• Rock of Ages 3: Make and Break
• Strange Brigade
• PUBG - Payback Edition
• Orcs Must Die! 3
• Crayta: Premium Edition
• West of Loathing
• Just Shapes & Beats
• Metro Last Light Redux
• Panzer Dragoon: Remake
• Little Nightmares
• Superhot
• Power Rangers: Battle for the Grid
• Embr Early Access
• SteamWorld Heist
• SteamWorld Dig
• SteamWorld Dig 2
• SteamWorld Quest: Hand of Gilgamech
• Destiny 2: The Collection
• Gylt

Dead by Daylight is the first game to feature Crowd Choice. A Youtuber can stream the game, while viewers decide which role (survivor or killer, and also which killer) the streamer plays the next round. Google says that in future more games will support this feature.

https://www.youtube.com/watch?v=m21HTd9qp9s

source: https://community.stadia.com/t5/Stadia-Community-Blog/This-Week-on-Stadia-Six-new-free-games-plus-Risk-of-Rain-2/ba-p/32956

last month: https://gamrconnect.vgchartz.com/thread/243230/stadia-pro-games-of-september/

that isn;t helping in light of luna

Thats a decent collection of games that they offered this month on top of the 23 available ones. But streaming games is not my cup of tea.

Meh, nothing really heavy hitting

stadia did not do a great 1st impression,
i dont even know what to think of them haha!

They need to spend some money to get at least one big AAA game per quarter in the Pro subscription within a couple months of launch., And maybe one of each year's big fall releases on launch day. The offering at this point is generally pretty decent. But, they need something exciting once in a while. I figure I will eventually give Stadia a try. But, there just hasn't been anything compelling enough to get me to go through the trouble and expense of signing up. I'm sure there are a bunch of other people in this same boat. Some excitng games once in a while would probably do the trick for many of us.

I agree, Stadia needs something big from time to time. Biggest things so far as I can see are Tomb Raider and Metro. Maybe Baldur's Gate will be included, Google added finance to the budget of the game. That would be big for me.

It’s funny how half of these games (Celeste, Jotun and Superhot) were already offered for free (not even subscribing) to Epic Games Store. Dead by Daylight was also free on PS Plus and Lara Croft and the Temple of Osiris was free on Steam during the pandemic. I feel Google is acting really cheap in regards to their Stadia subscription, so much so that I give it a lifetime of one or two more years until it’s abandoned completely. Luna, Xbox Game Pass, even PS Now look more enticing than Stadia. At least I hope the studios under their belt will thrive with multiplatform releases.