to get things going to practice of a job to practice a grammar point
General
eslconversationquestions.com
Large bank of conversation questions organized by grammar points. Some work and some don't, but the effort investing in this site is worth a trip.
sBusy Teacher
Hypothetical situation meant to fuel creative writing in first language students, but also work for discussion using the conditional verbs in the past, present and future.
ESLLounge.com
Super wealthy site full of interactive exercises. Mainly offers grammar and vocabulary practice, the site is organized by language level. A good place to find a quick intro or review exercise on a specific item.
UE English Grammar and Vocabulary
Superbe list of grammar and vocabulary quizzes. Each quiz is tagged with a language level which makes it easy to find what you need.
Verb Tenses
Perfect Tenses
TEFL.net
Always a tough tense to grasp, this site provides some questions to provoke responses using the present perfect tense. I can't guarantee that the rest of the discussion will continue in the perfect, but it's worth using it just to see if students are using the tense appropriately.
Never Ever Have I
Meant as a first language "truth or dare" type discussion, this site has some fun and weird questions that may get your students thinking about things they might have on their bucket list.
ESLConversation Questions
These questions may not generate deep discussions and some really only lead to a yes/no responses, but with a little teacher encouragement, you could have a rapid fire Q&A that drills the present perfect tense.
Future
Look into the Future
Hypothetical situations organized as role plays that talk about the future. It can be modified as discussion questions.
Will
Questions asking about future events...some concrete some hypothetical
Prepositions
Talk about your job preposition practice
This site starts with a practice drill to help elicit basic prepositions that can be combined with "work." Then if you scroll down you will notice a bunch of questions that relate to an actual person. It's a good way of scaffolding the conversation.
Prepositions of Time
Some quick Q&A to practice the time prepositions 'at', 'in', and 'on'.
ESL Q&A with prepositions
Simple and effective. This little ESL preposition exercise can serve as a way to elicit basic prepositions and then can be used to launch a general discussion. I like it.
Phrasal Verbs