These are all 20th-century claims, except the U.S.-wank: nationalism in the 19th-century Americas was different from Central and Eastern Europe's ethnic and romantic nationalisms. A Mexiwank would just be the Viceroyalty of New Spain. Note also that these are of varying strength (France officially tried to annex Saar, but I doubt few Poles are that hot about taking Brest by hook or by crook), and jumbled together regardless of time--all anachronistic.
Allohistorical disclaimer: I don't endorse any of these, nor do I affirm or deny that any of these are necessarily policy goals--past or present, official or popular. This maximalist sort of ethnic nationalism (created 1830-1930) works to unify numerous different histories, diverse languages and dialects, and local interests into a single and "eternal" bloc--to define a new, bigger ethnicity. It's produced indigenism, oaths, Lebensraum, mass games, camps, chanting, sentimentalism, Freedom Fries, renaming, chauvinistic national mysticism, homogenization campaigns at home and abroad, and perhaps worst of all, Roger Waters, Moby, and Sean Penn subjecting everyone to their opinion on geopolitics. This map is just to put every non-ASB wank and nationalist claim together at once.
Afghanistan misses the Pashtuns in Pakistan's Khyber Pakhtunkhwa and FATA.
Greater Albania wriggles its way into Ulcinj, Krajina, Preševo, Bujanovac, Medveđa, Western Macedonia, and Chameria.
Argentina, Bolivia, Ecuador, Guatemala, Suriname, Uruguay, Nicaragua, and Venezuela all have territorial demands on their neighbors.
Greater Armenia goes to the Sèvres border, Javakheti, Nakhichevan, and Karabakh.
Greater Australia I gave New Zealand and (arbitrarily) Western Papua.
Greater Azerbaijan takes Armenia, Iranian Armenia, Georgian Borchali, and Dagestan's Derbent.
Greater Bangladesh is a canard, but it'd include the Muslim parts of India nearby.
Greater Belarus covers Central Lithuania and Białystok.
Greater Bulgaria has the 1941 boundaries, covering Western Thrace, Vardar Macedonia, and the Western Outlands.
Pol Pot wanted a lot more for Cambodia.
both Chinas in fact claim Mongolia, Tuva, the Tajik Pamirs, Arunachal Pradesh, and a bit of Burma.
Greater Croatia has its 1939 boundaries.
Denmark was so stunned when it lost Flensburg in 1920 the government fell.
Egypt would've gotten Sudan had Ismail al-Azhari gotten his way.
Greater Finland slices into Scandinavia, Karelia, Ingria, Estonia, and Murmansk.
France's revanchism was mostly about Alsace, but the 1946 Monnet Plan demanded control of all the Rhineland, and worked to win over the Saar 1947-56. Action Française would no doubt have snapped up Wallonia, the Alps, and perhaps even Catalonia, given half the chance (though they never advocated for this, it's plausible). This would be like 13 or 17 new departments.
Greater Germany of course has the 1918 boundaries (I decided to leave un-Germanized Poznań out, however), Memel, Austria, the Sudetenland, and South Tyrol. Even West Germany didn't recognize the Oder-Neisse line until 1970, and signed with Poland 1990.
Venizelist Greece demands Northern Epirus, the Straits, Cyprus, the Pontic shores, and all Lydia.
Greater Hungary just has its 1941 borders--the Slovakian and Crișana fringes, Ruthenia, and northern Transylvania.
India and Pakistan have overlapping Kashmiri claims, which'd make either country rather bigger and stronger.
Greater Indonesia combines all Malay lands and ex-Portuguese and Dutch holdings.
Greater Iraq includes Shiite Saudi Bahrain (Qasim) and Khuzestan and Kuwait (Saddam).
Greater Israel is a Canaanist idea that includes Transjordan and Lebanon.
Greater Italy under Mussolini acquired Istria and Dalmatia, and would demand Malta, Corsica, Nice, Ticino, and occupied the Alpine passes.
Japan just wants the southern Kurils.
Greater Kazakhstan isn't an actual movement, but would get the Second East Turkestan Republic had Soviet firepower been used.
Lithuania wanted Suwałki and even Brest until it was invaded 1939.
United Macedonia adds Blagoevgrad and Greek Macedonia.
Greater Mongolia runs over Tuva, both Mongolias, Buryatia, and Altay.
Greater Morocco fought with Algeria and even Greater Mauritania over Western Sahara.
the Netherlands proposed the Bakker-Schut Plan against Germany 1945. A Greater Netherlands would snap up Flanders and Brussels (a Brabantine town, really...), and Vlaams Belang wouldn't mind French Flanders.
even Norway would want Jämtland back if it were megalomaniacal enough! Also Erik the Red's Land.
Pan-Arabism combines actual federations: AF, AIR, FAR, UAS, plus I added the Maghreb and excluded the Gulf Council. Libya also claimed Chad's Aozou Strip.
the Greater Philippines includes eastern Sabah and the Spratlies.
Poland already got its Recovered Territories after WWII, though there were suggestions to take the Sorbian lands, too. Its maximum extent nowadays would include Hrodna, Brest, the cultural capital of Lviv, Central Lithuania, and the Zaolzie.
Greater Portugal expands to Galicia, part of Asturias, and Olivença.
Greater Romania carves out Transnistria, all Bukovina, and Southern Dobruja, as IRL.
Greater Serbia marches up to Virovitica and Karlovac (after Šešelj).
United Slovenia stretches from Plebiscite Carinthia to Istria.
Greater Somalia goes into Ethiopia, Kenya, and Djibouti.
Greater South Africa is a White Pan-Africanism, covering Namibia and Southern Rhodesia (which voted "nay" in 1922).
Greater Spain under Franco proposed taking Portugal, Gibraltar, and the Pyrenees.
Sweden wants the Ålands for their Swedishness.
Greater Syria is absorbed under Pan-Arabism, but technically includes the Golan Heights, the Beqaa Valley, and Alexandretta.
Greater Turkey'd get Western Thrace, Adjara, and the Turks in the Bulgarian hills and Romanian lowlands. Pan-Turkism extends to Chuvashia and Tuva.
Greater Ukraine has Transnistria, Prešov, Chełm, Przemyśl, the Lemko towns of Nowy Targ and Sącz, Brest, Starodub, Belgorod, Kursk, and some Romanian borders. Also you have the Rostov and Kuban Cossacks and Ukrainians.
the United States has seen Canadian annexationism, William Walker ruling Sonora and Nicaragua in the 1850s; there were filibusters across the Río Grande as well in 1840. North Mexico is different enough from the rest that the Knights of the Golden Circle would be okay with annexing and colonizing it (as they did in TL-191, and the IRL Confederates even took Arizona). In the Caribbean of course there's the Ostend Manifesto for Cuba, the 1870 near-annexation of Santo Domingo, and the Panama Canal. Honduras's APROH did actually ask for U.S. annexation in the mid-1980s.
Greater Yemen was "reunited" 1990, but also includes ʿAsir, Bahah, Dhofar, Jizan, and Najran.
(Austria doesn't show a sign of expansionism at all. Although many people like me would like Südtirol back, it's unfortunately no serious topic in politics...)
If any fictious expansionism is needed, I'd say go either to Slovenia or to Hungary.