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