-ई

The suffix -ई has many uses.

Noun -> Feminine Noun (Vocation)

नौकर (servant) -> नौकरी (job, service)

Verb Stem -> Abstract Feminine Noun

बोल(ना) (to speak)-> बोली (speech, language)

Masculine Noun -> Diminutive Feminine Noun

डंडा (stick) -> डंडी (small stick)

Adjective -> Noun

अच्छा (good) -> अच्छाई (goodness)

Noun -> Noun / Adjective

हिन्दुस्तान -> हिन्दुस्तानी

विदेश (foreign country) -> विदेशी (foreign, foreigner)

जंगल (forest, jungle) -> जंगली (wild)

-अक

Certain nouns ending in -अन or ना are converted to an agentive noun by changing the -अन to -अक.
चिंतन (contemplation) -> चिंतक (thinker), आलोचना (criticism) -> आलोचक (critic), समर्थन (support) -> समर्थक (supporter)

-आव

The suffix -आव converts a verb stem to a noun. It comes from Hindi/Sanksrit.

चुनना (to choose) -> चुनाव (election, choice)
चढ़ना (to climb, ascend) -> चढ़ाव (upswing, ascent)
बदलना (to change) -> बदलाव (change)

अ-

The prefix अ means “not”, “un-“, “im-“, “without”, “-less”, etc. It comes from Sanskrit/Hindi.

With adjectives:

अ + संभव (possible) = असंभव (impossible)

अ + सफ़ल (successful) = असफ़ल (unsuccessful)

With nouns:

अ + हिंसा (violence) = अहिंसा (nonviolence)

अन-

The prefix अन means “without”, “not”, etc.

With adjectives:

अन + जाना (known) = अनजाना (unknown)

With nouns:

अन + अंत (end) = अनंत (endless)

-पन

The suffix पन converts adjectives (and occasionally nouns) into abstract nouns, like “-ness”, “-ity”, “-hood” in English. It comes from Sanksrit/Hindi. Nouns with this suffix are masculine.

पागल (insane) + पन = पागलपन (insanity)

अकेला (alone) + पन = अकेलापन (loneliness)

बच्चा (child) –> बचपन (childhood)

निर-  / नि-

The prefixes निर and नि mean “without”. It comes from Sanskrit/Hindi.

निर + दोष (blame) = निर्दोष (blameless, innocent)

नि + डर (fear) = निडर (fearless)

अप-

The prefix अप- indicates something bad, like “dis-“, “in-“, etc. in English. It comes from Sanskrit.

अप + मान (honor, respect) = अपमान (dishonor, disrespect, insult)
अप + शब्द (word) = अपशब्द (bad word, abuse)

कु-

The prefix कु- transforms a noun into a noun or adjective indicating something bad, evil, inferior, etc. It comes from Sanskrit/Hindi.

कु + प्रथा (practice / custom) = कुप्रथा (malpractice, bad custom)

कु + कर्म (deed) = कुकर्म (misdeed)

सु-

The prefix सु transforms a noun or adjective into another noun or adjective indicating something good. It comes from Sanskrit/Hindi.

सु + कर्म (deed) = सुकर्म (good deed)
सु + रक्षा (protection) = सुरक्षा (security, i.e. good protection)

दुर्-

The prefix दुर् indicates something bad or unfortunate. It comes from Sanskrit.

दुर् + घटना (event, incident) = दुर्घटना (accident)
दुर् +भाग्य (fortune, luck) = दुर्भाग्य (misfortune)

पुनर्-

The prefix पुनर्- is like “re-” in English. It comes from Sanskrit.

पुनर् + जन्म (birth) = पुनर्जन्म (rebirth)

स-

The prefix स- is like “-ful” in English; it indicates “with”, “together with”, or “full of”, etc. It comes from Sanskrit.

स + फल (fruit, result) = सफल (successful, fruitful)

स्व-

The prefix स्व- indicates “one’s own”, “self-“, etc. It comes from Sanskrit.

स्व + भाव (feeling, emotion) = स्वभाव (one’s own nature, temperament)

सह-

The prefix सह- indicates “together with”, “mutual”, “similar”, “same”, etc.

सह + योग (union) = सहयोग (cooperation)
सह + मत/मति (mind, thought) = सहमत (agreed), सहमति (agreement)

Words can have multiple prefixes, such as असहयोग.

ख़ुश-

The prefix ख़ुश- means “happy”, “fortunate”, “good”, etc. It comes from Persian.

ख़ुश + क़िस्मत (fate, luck) = ख़ुशक़िस्मत (good luck)

ग़ैर-

The prefix ग़ैर- indicates “ir-“, “il-“, “without”, etc. It comes from Arabic.

ग़ैर + क़ानूनी (legal) = ग़ैरक़ानूनी (illegal)
ग़ैर +ज़िम्मेदारी (responsibility) = ग़ैरज़िम्मेदारी (irresponsibility)

ना-

The prefix ना- indicates “not”, “without”, like “im-“, “in-“, “un-“, etc. It comes from Persian.

ना + लायक (worthy) = नालायक (unworthy)
ना + मुमकिन (possible, thinkable) = नामुमकिन (impossible, unthinkable)

बद-

The prefix बद- indicates something bad or unpleasant. It comes from Persian. It transforms a noun into an adjective or noun.

बद + सूरत (form, face, visage) = बदसूरत (ugly, unattractive)
बद + नाम (name) = बदनाम (infamous)

बे-

The prefix बे- indicates “without”. It comes from Persian.

बे + होश (consciousness, senses) = बेहोश (unconscious)

ला-

The prefix ला- indicates “without”. It comes from Arabic.

ला + परवाह (care) = लापरवाह (careless, reckless)

हम-

The prefix हम- indicates togetherness.

हम + सफ़र (journey, travel) = हमसफ़र (companion, fellow traveler)

-ता

The suffix -ता transforms an adjective into an abstract feminine noun. It comes from Sanskrit.

विभिन्न (different) + ता = विभिन्नता (difference)

-आई

The suffix -आई transforms a verb stem into a feminine noun. It comes from Hindi.

पढ़(ना) (to read/study) + आई = पढ़ाई (study, education)

-इक

The suffix -इक transforms a noun into an adjective. It comes from Sanskrit.

धर्म (religion) + इक = धार्मिक (religious)
परंपरा (tradition) + इक = पारंपरिक (traditional)

-ईय

The suffix -ईय transforms a noun into an adjective. It comes from Sanskrit.
शास्त्रीय (classical)
भारतीय (Indian)

In Hindi, adjectives are often made from cognate nouns by changing an initial vowel इ to the vowel ऐ and appending the suffix -इक (in maatraa form). Here are a few examples:
विश्व (world) -> वैश्विक (global / worldwide)
दिन (day) -> दैनिक (daily)
विकल्प (option)-> वैकल्पिक (optional)

-आवट

The suffix -आवट transforms a verb stem into a feminine noun. It comes from Hindi.

दिख(ना) (to appear) + आवट = दिखावट (appearance)

-आ

The suffix -आ changes a verb stem into a masculine noun. It comes from Hindi.

झगड़(ना) (to fight) + आ = झगड़ा (fight, quarrel)

-त्व

The suffix -त्व changes a noun or adjective into an abstract masculine noun.

पुरुष (man) + त्व = पुरुषत्व (virility, manliness)

-पूर्ण

The suffix -पूर्ण indicates “full of”, etc.

महत्व (important) + पूर्ण = महत्वपूर्ण (importance)

-ईयत

The suffix -ईयत transforms an adjective into an abstract noun.

अहम (important) + -ईयत = अहमियत (importance)

-पूर्वक

The suffix -पूर्वक turns a noun into an adverb.

ध्यान (attention/care) + पूर्वक = ध्यानपूर्वक (attentively, carefully)

-मान

The suffix -मान converts a noun into an adjective. It comes from Sanskrit.

बुद्धि (wisdom/intelligence) + मान = बुद्धिमान (wise, intelligent)

-आना

The suffix -आना converts a noun into an adjective or different noun. It comes from Persian.

साल (year) + आना = सालाना (annual)

-दार

The suffix -दार converts a noun into another noun or an adjective. It comes from Persian.

दुकान (shop) + दार = दुकानदार (shopkeeper)

ईमान (trust) + दार = ईमानदार (honest)

-नाक

The suffix -नाक indicates “full of”. It comes from Persian.

ख़तरा (danger) + नाक = खतरनाक (dangerous)

-ख़ाना

The suffix -ख़ाना indicates a place where something is located, etc. It comes from Persian.

ग़ुसल (washing) + ख़ाना = ग़ुसलख़ाना (washroom, bathroom)

-ईन

The suffix -ईन converts a noun to an adjective. It comes from Persian.

नमक (salt) + ईन = नमकीन (salty snack)

-मंद

The suffix -मंद converts a noun into an adjective. It comes from Persian.

अक़्ल (wisdom, intelligence) +  मन्द =  अक़्लमन्द (wise, intelligent)