Here are a few commonly used gems I like and their alternatives
Ruby program to Calculate the factorial of given number
Ruby program to reverse a string
Creating Array with Array.new(size, obj) in Ruby
Ruby program to check whether the given number is Armstrong
Ruby program to generate random numbers
Ruby program to print Fibonacci series
What's the difference between a lambda, a block and a proc?
How to Sort Array in Ruby?
How to create two dimensional array in ruby?
Ruby program to add two integer numbers
How to get index of array element in Ruby
How to shuffle an array in Ruby?
How to Get Input with Gets in Ruby
How to Replace array elements in Ruby?
Ruby program to check whether the given number is palindrome
Program to Print Triangle of Numbers in Ruby
how to create an array with Array.[](*args) in Ruby ?
Ruby program to print an array
How to add/remove elements to Array in Ruby?
Ruby program to check whether the given number is prime or not
What are the various Ruby runtimes, and how are they different?
What are #method_missing and #send? Why are they useful?
What are some of your favorite gems? What are their alternatives?