Below are some potential notable starts being made by drivers this weekend. Notable meaning they will be tied with a driver in number of starts made in that specific series, or the number of starts being made is a significant number that they are reaching in their specific race this weekend at the Sonoma Raceway. Rankings reflect the all-time starts list for that series.
(The image above each series is the driver I find having the most notable start this weekend)

*This will be updated after qualifying for each race if a driver does not make the race.

Kyle Sieg will be making his 100th career Xfinity Series start this weekend at Sonoma. Image credit: @RSSRacing__ X Page

Xfinity Series Starts

Brandon Jones: 321st start ties Michael Annett, ranks 23rd

Brennan Poole: 176th start ties Cole Custer, ranks 88th

Alex Labbe: 161st start ties Ward Burton, ranks 100th

Ryan Ellis: 150th start! Ranks 108th

Sam Mayer: 136th start ties Dale Earnhardt, ranks 121st

Austin Hill (#21): 133rd start ties Austin Cindric, ranks 125th

Sheldon Creed: 122nd start ties Parker Kligerman, ranks 141st

Josh Bilicki: 119th start ties Kyle Larson, ranks 146th

Matt DiBenedetto: 116th start ties Ken Schrader, ranks 151st

Kyle Sieg: 100th start!

Blaine Perkins, Harrison Burton & Sammy Smith: 94th start ties Geoff Bodine, Michael McDowell & Tony Stewart, ranks 182nd

Parker Retzlaff: 93rd start ties Jimmie Johnson, ranks 188th

Connor Mosack: 30th start ties Boris Said & Kurt Busch, ranks 359th

*Austin Hill (#35): 1st start!

*Austin Hill (#35) did not qualify for the race and thus will not be making his 1st career Xfinity Series start.

Christopher Bell is making milestone start number 200 in the Cup Series this weekend at Sonoma. Image credit: @JoeGibbsRacing X Page

Cup Series Starts

Austin Dillon: 428th start ties Derrike Cope, ranks 65th

Ryan Blaney: 362nd start ties Neil Bonnett, ranks 80th

Bubba Wallace: 275th start! Ranks 111th

Ryan Preece: 207th start ties Alan Kulwicki, ranks 142nd

Christopher Bell: 200th start! Ranks 150th

Todd Gilliland: 128th start ties A.J. Foyt, ranks 202nd

Shane Van Gisbergen: 34th start ties Parnelli Jones, ranks 392nd