diff --git a/internal/prepare.go b/internal/prepare.go
index e6614b16..e4521ca6 100644
--- a/internal/prepare.go
+++ b/internal/prepare.go
@@ -25,6 +25,7 @@ import (
 	"os"
 	"path/filepath"
 	"regexp"
+	"strconv"
 	"strings"
 	"time"
 
@@ -38,11 +39,18 @@ import (
 )
 
 var (
-	charset = []rune("abcdefghijklmnopqrstuvwxyz0123456789")
+	charset                  = []rune("abcdefghijklmnopqrstuvwxyz0123456789")
+	charsetLowercaseLetters  = []rune("abcdefghijklmnopqrstuvwxyz")
+	charsetUppercaseLetters  = []rune("ABCDEFGHIJKLMNOPQRSTUVWXYZ")
+	charsetLetters           = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+	charsetAlphanumeric      = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")
+	charsetAlphanumericLower = []rune("abcdefghijklmnopqrstuvwxyz0123456789")
 
 	dataSourceRegex = regexp.MustCompile(`\${data\.(.*?)}`)
 	randomStrRegex  = regexp.MustCompile(`\${Rand\.(.*?)}`)
 
+	defaultRandomStrLength = 8
+
 	caseDirectory = "case"
 )
 
@@ -153,10 +161,32 @@ func (p *preparer) injectValues(manifestData string, dataSourceMap map[string]st
 	// Inject random strings
 	randomKeys := randomStrRegex.FindAllStringSubmatch(manifestData, -1)
 	for _, randomKey := range randomKeys {
-		switch randomKey[1] {
+		randStrLength := defaultRandomStrLength
+		randKind, randLength, found := strings.Cut(randomKey[1], "#")
+		if found {
+			if rsr, err := strconv.Atoi(randLength); err == nil && rsr > 0 {
+				randStrLength = rsr
+			}
+		}
+		switch randKind {
 		case "RFC1123Subdomain":
 			r := generateRFC1123SubdomainCompatibleString()
 			manifestData = strings.Replace(manifestData, randomKey[0], r, 1)
+		case "Alphanumeric":
+			r := generateAlphanumericString(randStrLength)
+			manifestData = strings.Replace(manifestData, randomKey[0], r, 1)
+		case "AlphanumericLowercase":
+			r := generateAlphanumericLowercaseString(randStrLength)
+			manifestData = strings.Replace(manifestData, randomKey[0], r, 1)
+		case "LettersLowercase":
+			r := generateLowercaseLetterString(randStrLength)
+			manifestData = strings.Replace(manifestData, randomKey[0], r, 1)
+		case "LettersUppercase":
+			r := generateUppercaseLetterString(randStrLength)
+			manifestData = strings.Replace(manifestData, randomKey[0], r, 1)
+		case "Letters":
+			r := generateLetterString(randStrLength)
+			manifestData = strings.Replace(manifestData, randomKey[0], r, 1)
 		default:
 			continue
 		}
@@ -172,3 +202,34 @@ func generateRFC1123SubdomainCompatibleString() string {
 	}
 	return fmt.Sprintf("op-%s", string(s))
 }
+
+func generateStringWithCharset(charset []rune, length int) string {
+	if length < 1 {
+		length = defaultRandomStrLength
+	}
+	s := make([]rune, length)
+	for i := range s {
+		s[i] = charset[rand.Intn(len(charset))] //nolint:gosec // no need for crypto/rand here
+	}
+	return string(s)
+}
+
+func generateAlphanumericString(length int) string {
+	return generateStringWithCharset(charsetAlphanumeric, length)
+}
+
+func generateAlphanumericLowercaseString(length int) string {
+	return generateStringWithCharset(charsetAlphanumericLower, length)
+}
+
+func generateLowercaseLetterString(length int) string {
+	return generateStringWithCharset(charsetLowercaseLetters, length)
+}
+
+func generateUppercaseLetterString(length int) string {
+	return generateStringWithCharset(charsetUppercaseLetters, length)
+}
+
+func generateLetterString(length int) string {
+	return generateStringWithCharset(charsetLetters, length)
+}