First person pronouns
Spanish along with other South-west Romance languages have two wes: masculine nosotros and feminine nosotras. In those cases, can also exist a third one, a gender-neutral we, like Occitan nos or Sardinian nois.
Sloven has four wes: two masculine (midva and mi) and two feminine (medve / midve and me). Midva and midve are used for two people (thus called dual) and for more people, mi and me. Sami languages have dual as well. Old English used to have it: dual wit and plural we.
In the Caucasus, Avar, Chechen and Ingush, have also two wes but they are not differenciated according to gender nor number. For example, in Chechen, both тхо (tχo) and вай (waj) mean “we”. However the first one is exclusive and the second, inclusive. This is called clusivity. It means that тхо includes the speaker and the addressee but вай does not include the addressee.
Second person pronouns
The second-person pronoun in English, you, is a rarity among the European languages. Unlike other modern languages English does not differenciate singular and plural anymore. Old English, however, did and in fact there was even a third pronoun: þū (singular you), ġit (dual you) and, ġē (plural you). Later dual dissappeared, not only in English.
In the 17th century you (originally plural) took over the place of the nowadays archaic thou (you singular). The use singular and plural forms for informal and formal connotations is called the T–V distinction. It happens in many languages. Like in French tu (singular, informal) and vous (plural informal and formal), it happens in many other languages.
Some languages have a third pronoun. It is the case of German: du (singular informal), ihr (plural informal) and Sie (formal).
Like in the first-person pronouns, in the Iberian peninsula some languages have gendered informal pronouns like Galician vosoutros and vosoutras. Portuguese and Polish use a similar strategy. Both have two pairs of gendered formal pronouns, that originated from the nouns lady and gentelman (pani and pan), ladies and gentelmen (panie and panowie), and a fifth gender-neutral plural (Państwo).
Third person pronouns
The language with the highest number of third-person pronouns is Slovene. It has three pairs (singular, dual and plural) of masculine, femenine and neutrum.
On the other hand Basque, Hungarian, Finic and Turkic languages has just two, singular and plural.
The most peculiar is Romanian. In this language exist along with the two pairs of pronouns (singular: el and ea, plural: ei and ele), there are another two pairs to address someone you are talking about formally.