I really like the verbs that add a g after the stem in the yo present form. It’s attractive how “I” gets a little extra flair when the rest of the folks stay relatively normal. You get the sense quickly how there are really only a couple of patterns to these guys. First, there are the poner-like verbs. They add the g to yo (pongo), but they are otherwise predictable: tú pones, ella pone, nosotros ponemos, vosotras ponéis, ustedes ponen.
Next, you have the tener-like verbs that include an e to ie vowel shift besides adding the g: yo tengo, tú tienes, él tiene, nosotras tenemos, vosotros tenéis, ellos tienen.
Then there are the caer-traer verbs, which add an i in the yo form (caigo) but are otherwise predictable: tú caes, ella cae, nosotros caemos, vosotras caéis, ellas caen.
And finally screwballs like oír, which shifts i to y to avoid having three vowels in a row: yo oigo, tú oyes, usted oye, nosotras oímos, vosotros oís, ustedes oyen. Or verbs like decir, which just don’t play well with others period: yo digo, tú dices, él dice, nosotros decimos, vosotras decís, ellos dicen.
The fun thing is that once you have these patterns down there’s a whole exciting world of go verbs out there that are waiting to be conjugated…at least in the present (many g verbs are irregular in other tenses, too). Like raer (raigo, raes), which means “to scrape” or “to rub off,” or the strange compound verb satisfacer (conjugated like hacer), which shockingly means “to satisfy.” More importantly, there are quite a few verbs that are just a core yo-go verb like poner, decir, or tener with a sweet prefix added on. The meaning of words like bendecir (“to bless”), maldecir (“to curse”), and predecir (“to predict”) should be easy to guess and have a beautiful simplicity about them, if you ask me. I particularly like deshacer (“to destroy”–to unmake) and convenir (“to agree”–to come together with).
Here are a few others I’ve come across:
poner: componer (“to compose”), oponer (“to oppose”), suponer (“to suppose”)
tener: abstenerse (“to abstain”), atenerse (“to rely on”), contener (“to contain”), detener (“to stop” someone or something), detenerse (“to stop” oneself), mantener (“to maintain”), obtener (“to obtain”), sustener (“to sustain”)
traer: atraer (“to attract”)