A few party emblems for a (semi-)pluralistic United States with a fairly early PoD (and it's very much inspired by a map I'm working on). All of these five parties are represented in at least one chamber of congress. Sorry that they aren't super imaginative.
The first emblem (left in the top row) is for the Atlantic Party of America, a conservative liberal party that was founded primarily with the issue of ending American isolationism and increasing diplomatic and trade ties with the other nations on the Atlantic coasts. Ideologically think Rockefeller Republican. It is the third-biggest party and frequently tips the scales on battles in congress.
The next emblem (middle in the top row) is the Republican Party, the successor to the Democratic-Republican Party. It's conservative, isolationist, and has a significant libertarian faction. Together with the Farmer-Labor Party it's one of the two big parties.
The last emblem in the top row is the aforementioned Farmer-Labor Party. It's a democratic socialist party with an emerging green politics wing and is divided on the issue of foreign policy but tends to be very skeptical of trade deals.
The fourth party is the Popular Party of Cuba, a separatist party that advocates for, big surprise, Cuban interests in general and partially Cuban independence. It's rather center-left but also has a "pure" centrist faction. Also has a chapter in Florida to represent the interests of Cubans (and Spaniards) living there. [Oh and in case you wanted to ask: yes, I drew that Cuban trogon on the logo myself.]
Last but not least is the Free Texas Party, which is a Texan nationalist party. It often aligns itself with the Republican Party in terms of economic and social issues but the strong Texan identity ensures the party's survival. While primarily active in Texas it also has chapters in Oklahoma and Comancheria.