Any hotel or vacation rental near downtown will work but here are some we recommend for instant booking and great locations/past reviews:
https://inncahoots.com/property/inn-cahoots-hotel-unit-1?discountCode=Spark (holds 20+ people; promo code “Spark” should auto-load for a 5% discount). They can add beds if necessary and the properties are in hotel zones so parties are OK here or
https://inncahoots.com/property/6th-street-skyline-townhouse?discountCode=Spark (holds up to 20 people; promo code “Spark” should auto-load for a 5% discount). They can add beds if necessary and the properties are in hotel zones so parties are OK here
https://inncahoots.com/property/downtown-single-malt-manor?discountCode=Spark (Use promo code “Spark” for a 5% discount). This holds 14 people and has 11 beds. It can combined with the unit above to hold 28 people.
https://www.vrbo.com/search/keywords:austin-tx-usa/arrival:2020-12-07/departure:2020-12-10/filter:email@example.com,-97.7775439937476,30.311330892180997,-97.70430359438694,13z/minBedrooms/4?petIncluded=false&ssr=true&adultsCount=10 This search includes all great locations and instant confirmation. Adjust dates and other filters to match your needs.
https://www.vrbo.com/783312 Coronavirus seclusion special: This house sits right on the Lake Travis shore and can hold 20+ people. They can provide catering and they own a party boat company too so you can seclude and have fun partying with your buddies in this COVID-19 world (assuming you don’t want to be in the downtown crowds/bars).