Disclaimer: I am not a Spanish speaker, nor have I studied Spanish to any real extent. (I've done some self-study via textbooks and online apps/websites like Duolingo.) However, I know a bit about Spanish pronunciation/phonetics because I'm interested in linguistics and I have read some articles or web pages about it.
Spanish has many cases where the pronunciation of the end of a word changes based on the sound at the start of the following word (or vice versa). But my understanding is that the processes involved are usually not particularly similar to French liaison; rather, in most cases, the Spanish pronunciation phenomena could be thought of as "allophonic" processes.
As you've said in your question, French "liaison" is a very specific phenomenon that clearly involves phonological processes, and is not just a matter of allophony: for example, in the phrase "les amis" /lezami/, the phoneme /z/ is used between /e/ and /a/, even though there is no general rule of French pronunciation that absolutely prohibits vowel-vowel sequences like /ea/ (as in "idéal") or /ɛa/.
There are a few cases in Spanish of words having special phonological forms conditioned by the form of another word: for example, the definite article typically takes the form "el" when it comes directly before a feminine noun starting with stressed /a/, but "la" before other feminine nouns. But as far as I know, this kind of thing is quite rare in Spanish.
One thing that does occur in Spanish especially at word boundaries is " synalepha": two adjacent vowels across word boundaries tend to be pronounced in the same syllable. Vowels in this context apparently behave differently from word-internal vowels in hiatus, so I think we do have to mention word boundaries in the formulation of this rule.
Aside from this, many allophonic processes in Spanish apply at the (prosodic) phrase level rather than at the word level, including the allophony of "d" that you mentioned. See guifa's answer to How should I pronounce the Spanish consonant 'd'?
My understanding is that the allophony of "b/v" and "g" follows the same pattern. Many parts of Spanish pronunciation vary by dialect, however, so I don't know if it's possible to give a comprehensive description of the processes that may apply. For example, the coda nasal assimilates in place to a following consonant across word boundaries in many dialects, but in others I believe it is always velar [ŋ].
I don't know too much about this following topic, but the "aspiration" of word-final /s/ is I believe another area where pronunciation may vary based on the following sound.