The present indicative tense has a lot of irregular verb conjugations. It is easiest to learn once you understand that there is generally a pattern to the irregularities.
Verbs that are irregular in the yo form only.
caber (to fit) → quepo, cabes, cabe, cabemos, cabéis, caben
caer (to fall) → caigo, caes, cae, caemos, caéis, caen
conocer (to know) → conozco, conoces, conoce, conocemos, conocéis, conocen
There are a bunch of verbs that are like conocer. The irregularity is that you need to add a z just before the last c.
|aborrecer (to hate)||desconocer (be be ignorant of)||ofrecer (to offer)|
|agradecer (to thank)||establecer (to establish)||parecer (to seem)|
|aparecer (to appear)||estremecerse (to shudder)||permanecer (to remain)|
|carecer (to lack)||merecer (to deserve)||pertenecer (to belong)|
|crecer (to grow)||nacer (to be born)||reconocer (to recognize|
|desaparecer (to disappear)||obedecer (to obey)||traducir (to translate)|
dar (to give) → doy, das, da, damos, dais, dan
hacer (to do, to make) → hago, haces, hace, hacemos, hacéis, hacen
poner (to put, to place) → pongo, pones, pone, ponemos, ponéis, ponen
saber (to know) → sé, sabes, sabe, sabemos, sabéis, saben
salir (to go out, to leave) → salgo, sales, sale, salimos, salís, salen
traer (to bring) → traigo, traes, trae, traemos, traéis, traen
valer (to be worth) → valgo, vales, vale, velemos, valéis, valen
ver (to see, to watch) → veo, ves, ve, vemos, veis, ven
While there are more irregular verbs in Spanish, they tend to be compound verbs that contain the previous irregular verbs as a base.
deshacer, imponer, componer, atraer etc.
As you learn new verbs, look for a possible root verb that you may already know.