A non-exhaustive list. The list includes a maker name and a year. The year is not specific other than it is the nominated year for a model that had a round radiator. Earlier and later models by the same maker may have been different in shape.
Round radiator
Bentall 1908 : The British made Bentall vehicles circas 1908 all sported a circular radiator. This had both a circular housing and inner core with the bboth circles being concentric. Some archive photos feature a stylised Bentall logo in the upper left quadrant of the core. The starter crank is mounted below the radiator and the filling cap is top dead centre.
https://www.itsaboutmaldon.co.uk/bentall-car/
https://maldon.nub.news/news/local-news/historic-maldon-district-the-bentall-motor-car
https://commons.wikimedia.org/wiki/Category:Bentall_vehicles#/media/File:MHV_Bentall_16-20_hp_Tourer_1908.jpg
This image is reputed as a Bentall, however the radiator shows clearly that the top of the core is squared off meaning it is not fully circular and inconsistent with every other image of a Bentall vehicle.
Delaunay-Belleville 1914 : https://en.wikipedia.org/wiki/Delaunay-Belleville
The models c1910 have a circular radiator core with the larger outer housing being eccentric to the inner core. The starter crank is mounted either on the outer edge of the housing or appears between the core edge and the outer edge of the housing.
Franklin 1907 : A circular inner core with an ovoid housing very narrow shroud around the upper section of the core with no filler cap. https://en.wikipedia.org/wiki/Franklin_%28automobile%29
Germain 1908 : Made in Belgium the models featured a rounded radiator outer and core with both being more ovoid than circular and eccentric.
Hotchkiss 1908 : These vehicles have a rounded radiator housing but generally have both the bottom and top of the core squared-off. https://en.wikipedia.org/wiki/Hotchkiss_(car)
The radiator in the key image above has had the badge removed and is unlikely to be working. It was probably stripped from one of Dad’s broken model purchases in the 1950’s.
Hudson 1913 : This maker did use some ovoid-shaped radiators in the 1910’s but later changed as body styles became streamlined. https://en.wikipedia.org/wiki/Hudson_Motor_Car_Company.
Maudslay 1909 : Some of the models sported a circular radiator but the eccentric core was displaced towards the bottom edge of the housing leaving a larger space between the top of the core edge the outer top edge of the housing just below the filler cap. http://classiccars.brightwells.com/viewdetails.php?id=11362
McIntyre 1909 : An ovoid radiator housing with an octagonal inner core shape. https://en.wikipedia.org/wiki/McIntyre_Automobile
Ours 1907 : “SA des Automobiles Ours” Paris build vehicles with a circular radiator with the core and outer being concentric. https://www.allcarindex.com/production/france/ours/
Rainier 1908 : A circular outer radiator housing squared-off at the bottom with the inner core rounded at the sides and squared-off top and bottom. https://en.wikipedia.org/wiki/Rainier_Motor_Car_Company
Nacke 1906: Very few photos but appears to be square or ovoid radiators.
Nordenfelt 1908 : Radiator with both curved and straight edges varying on both the core and housing. Straight sides to both with the outer rounded upper and lower. The core however is rounded at the bottom but having 3 sides of a hexagon in the upper section, i.e. the top is squared off to the sides but with 45degree corners cut off. https://www.allcarindex.com/search.html?name=Nordenfelt
Serpollet 1904 : Ovoid rather than circular.
Sheffield-Simplex 1914 : The outer housing is curved in both the shape side to side and the front to back profile. The inner core is squared-off at the top and appears to be convex to the front continuing the rounded profile of the housing, rather than the common flat face of radiators of the era.
Wolfe 1907: Rounded top of housing but square or rectangular core.
Wolseley 1907 : Rounded housing, mainly at the top, but apparently all square or rectabgular cores.